Twins, Dizygotic

Twins, Monozygotic

Diseases in Twins

Twins

Twins, Conjoined

Twin Studies as Topic

Pregnancy, Twin

Environment

Triplets

Pregnancy, Multiple

Twinning, Monozygotic

Pregnancy

Gene-Environment Interaction

Genetics, Behavioral

Registries

Inheritance Patterns

Maternal Serum Screening Tests

Fetofetal Transfusion

Denmark

Heredity

Quantitative Trait, Heritable

Birth Weight

Genetic Predisposition to Disease

Models, Genetic

Infant, Newborn

Phenotype

Chimerism

Chorion

Sweden

Social Environment

Siblings

Finland

Cohort Studies

Risk Factors

Maternal Age

Handwriting

FSHB

Epigenetics

List of twin towns and sister cities in Africa

List of twin towns and sister cities in Jordan

Jeddah

List of twin towns and sister cities in Cuba

List of twin towns and sister cities in Asia

Cause of obsessive-compulsive disorder

Twins and handedness

Aslaug Sverdrup Sømme

Twin study

West Indian manatee

Bruno Reversade

Prenatal testosterone transfer

Sleep

University of Birmingham

Growth differentiation factor-9

Patriarchy

Crohn's disease

Familial natural short sleep

George Shrinks

Ossification of the posterior longitudinal ligament

Ulcerative colitis

Twin

Yoruba people

Multiple birth

Heritability

Conjoined twins

Alcoholic liver disease

Pairs28

• In violation of Weinberg's Differential Rule, there are significantly more SS than OS pairs among dizygotic twins in nationally representative samples both in the UK and the USA. (medscape.com)
• The proportion of SS pairs among dizygotic twins was 0.6043 ( t (325) = 3.838, P = 0.00015) in the UK and 0.5739 ( t (520) = 3.398, P = 0.00073) in the USA. (medscape.com)
• Weinberg's Differential Rule may be incorrect in its assumption of independence of sexes within dizygotic pairs, and there may be evolutionary selection for SS, and against OS, dizygotic pairs. (medscape.com)
• Second, recent research in developmental psychology and biology also questions the independent determination of sexes in DZ twin pairs. (medscape.com)
• Results: A total of 2178 monozygotic, 3219 same-sex dizygotic, and 3014 unlike-sex dizygotic twin pairs provided information. (elsevierpure.com)
• In men, the intraclass correlation for reflux was 0.29 (95% confidence interval [Cl], 0.15-0.43) for monozygotic and 0.13 (95% Cl, 0.02-0.25) for dizygotic pairs. (elsevierpure.com)
• In women, the correlation was 0.33 (95% Cl, 0.22-0.44) for monozygotic and 0.14 (95% Cl, 0.04-0.24) for dizygotic pairs. (elsevierpure.com)
• For unlike-sex dizygotic pairs, the correlation was 0.06 (95% Cl, -0.01 to 0.14). (elsevierpure.com)
• Conclusions: The increased concordance for reflux in monozygotic pairs, compared with dizygotic pairs, indicates genetic rather than shared environmental effects. (elsevierpure.com)
• We studied 4042 Vietnam era veteran monozygotic and dizygotic male twin pairs to determine the effects of heredity, shared environment, and unique environment on the liability for 15 self-reported posttraumatic stress disorder symptoms included in the symptom categories of reexperiencing the trauma, avoidance of stimuli related to the trauma, and increased arousal. (nih.gov)
• Symptoms in the reexperiencing cluster and one symptom in the avoidance and numbing cluster are strongly associated with combat exposure, and monozygotic pairs are more highly concordant for combat exposure than dizygotic pairs. (nih.gov)
• There were no significant differences in site concordance of EH within the MZ twin pairs compared with DZ twin pairs when only presence of EH was considered, whereas a greater concordance was noted between MZ twin pairs compared with DZ twin pairs when both presence and absence of EH were considered. (edu.au)
• Data were collected from 10 adult twin pairs (5 MZ, 5 DZ) in which both twins already had a SARS-CoV-2 infection. (frontiersin.org)
• The aims of the current study were to estimate the relative influence of genetic and environmental factors on objective intermediate asthma phenotypes and, more importantly, to what extent correlations between these intermediate phenotypes can be explained by genetic and/or environmental factors using a sample of 103 young Dutch twin pairs. (ersjournals.com)
• The authors used structural equation modelling to perform a meta-analysis of data from these studies and an existing twin study to estimate ALS heritability, and identified 171 twin pairs in which at least one twin had ALS. (bmj.com)
• Results and discussion Five monozygotic twin pairs were concordant-affected, and 44 discordant-affected. (bmj.com)
• No dizygotic twin pairs were concordant-affected, and 122 discordant-affected. (bmj.com)
• Statistical models used to analyse twin data include "classical" analysis of variance components, and "twin differences" models that compare twins within monozygotic (MZ - identical) or dizygotic (DZ - fraternal) pairs. (twins.org.au)
• This design allows treatments to be compared within twin pairs, which enables near-perfect (for MZ twins) or partial (for DZ twins) control for genetics and shared environment, removing noise from the treatment effect estimate. (twins.org.au)
• gains in power (compared with assigning all twin pairs to the same group) will be achieved by comparing treatments within twin pairs assigned to differing interventions. (twins.org.au)
• By analyzing twin pairs, researchers determined that most of the variability in the immune system is due to environmental factors, rather than genes. (nih.gov)
• To determine the basis of immune system variation, a team led by Dr. Mark M. Davis at Stanford University School of Medicine applied the most recent advances in immune monitoring technologies to a classic research model: studying twin pairs. (nih.gov)
• Twin pairs share the same prenatal environment and usually have a similar childhood environment. (nih.gov)
• Of the 105 twin pairs, 78 were identical and 27 were fraternal. (nih.gov)
• We estimated familial correlations in DNAm age for monozygotic (MZ) twin, dizygotic (DZ) twin, sibling, parent-offspring, and spouse pairs by cohabitation status. (sens.org)
• These correlation patterns were best explained by cohabitation-dependent shared environmental factors, the effects of which were 1.41 (95% confidence interval [CI] 1.16 to 1.66) times greater for MZ pairs than for DZ and sibling pairs, and the latter were 2.03 (95% CI 1.13 to 9.47) times greater than for parent-offspring pairs. (sens.org)
• An Internet bulletin board search and clinical contact requests for participants in a survey of twins in which one or both transitioned located 69 new twin pairs. (hawaii.edu)
• Combining data from the present survey with those from past-published reports, 20% of all male and female monozygotic twin pairs were found concordant for transsexual identity. (hawaii.edu)

Concordance3

• Methods: We compared concordance for reflux in monozygotic (MZ) and dizygotic (DZ) twins. (elsevierpure.com)
• This study examined prevalence and site concordance of EH and opacity in the primary dentition of 2- to 4-year-old twins and singleton controls to assess the relative contribution of genetics and the environment to the aetiology of these defects. (edu.au)
• Monozygotic twins have a much higher concordance rate than dizygotic twins. (merckmanuals.com)

Genetics10

• Is the probability of having twins determined by genetics? (medlineplus.gov)
• However, a few families with a larger-than-expected number of MZ twins have been reported, which indicates that genetics may play a role. (medlineplus.gov)
• Shur N. The genetics of twinning: from splitting eggs to breaking paradigms. (medlineplus.gov)
• Even identical twins who share appearance and genetics do not have the same handwriting. (wikipedia.org)
• NIMH Grantee Art Petronis, M.D., Ph.D., University of Toronto, and colleagues, report on their findings in identical and fraternal twins in the February, 2009 issue of Nature Genetics . (nih.gov)
• Therefore, comparing traits between MZ and DZ may help to capture the determining part of genetics and environmental factors. (frontiersin.org)
• In a report published in the 2007 edition of the Journal of Human Genetics (per BBC ), the term semi-identical - or sesquizygotic - first surfaced as a descriptor for a type of twins. (scarymommy.com)
• The former models allow the variance of health and other outcomes to be partitioned into components due to genetics, shared (familial) environment and non-shared (twin-specific) environment. (twins.org.au)
• The latter models control for maternal and paternal factors, gestational age, geographical location and season of birth, age, ethnicity, sex (in MZ and same-sex DZ twins), and genetics (100% in MZ twins and 50% in DZ twins). (twins.org.au)
• The responses of our twins relative to their rearing, along with our findings regarding some of their experiences during childhood and adolescence show their identity was much more influenced by their genetics than their rearing. (hawaii.edu)

Triplets7

• Approximately 9% of ART singletons, 57% of ART twins, and 95% of ART triplets or higher-order multiples were low birthweight. (cdc.gov)
• Similarly, 15% of ART singletons, 66% of ART twins, and 97% of ART triplets or higher-order multiples were born preterm. (cdc.gov)
• at multiple sites and contains siblings (i.e., family_ID) and twins/triplets (i.e., sib). (nih.gov)
• Are they all twins/triplets? (nih.gov)
• Do you differentiate monozygotic (MZ) and dizygotic (DZ) twins/triplets? (nih.gov)
• I hadn't even thought it might be twins, let along triplets, and we haven't got any in the family. (dailymail.co.uk)
• For example, in one 2009 study published in the journal Neuropsychologia of 30,161 Finnish subjects between the ages of 18 and 69, left-handedness was more common in twins (8.1 percent) than in triplets (7.1 percent) and single borns (5.8 percent). (bestlifeonline.com)

Opposite-sex4

• Are There More Same-Sex Than Opposite-Sex Dizygotic Twins? (medscape.com)
• It was in this context that the French statistician Jacques Bertillon (1874) first speculated that the number of DZ twins would equal twice the number of opposite-sex (OS) twins and that the remaining twins would be MZ. (medscape.com)
• Using a sample of 3,349 (1,449 monozygotic (MZ), 1,105 dizygotic (DZ) same-sex (DZss) and 795 DZ opposite-sex (DZos)) twins, we showed that positive schizotypy, specifically, the perceptual and ideational components of schizotypy, correlated on a phenotypical level with neuroticism (Pearson's r=.37). (uni-muenchen.de)
• This report is both a review of previously reported findings and the result of a specific research effort to find twins among whom one or both had transitioned from their assigned sex at birth to the gender typical of the opposite sex. (hawaii.edu)

Monochorionic6

• Monochorionic diamniotic dizygotic (MCDADZ) twins are extremely rare. (e-kmj.org)
• In a mo/di pregnancy (more scientifically referred to as a monochorionic diamniotic pregnancy) the twins share a chorionic sac, but have different amniotic sacs. (healthline.com)
• In a mo/mo pregnancy (more scientifically referred to as a monochorionic monoamniotic pregnancy) the twins share both the chorionic and amniotic sacs. (healthline.com)
• Multiple pregnancies in humans account for only 3% of pregnancies, 97-98% of which are twin pregnancies and the morbimortality is higher in the monochorionic twins when compared to dichorionic ones. (scielo.br)
• The canine species is naturally multiparous, but the diagnosis of monochorionic twin pregnancy is not common. (scielo.br)
• Case Report: Identification of Germline Chimerism in Monochorionic Dizygotic Twins. (cdc.gov)

Siblings5

• Fraternal twins come from two eggs that are fertilized by two separate sperm and are no more alike than other siblings born to the same parents. (kidshealth.org)
• On the other hand, fraternal twins only share about 50 percent of their chromosomes, as other siblings do. (healthline.com)
• different numbers of subjects and siblings/twins per site. (nih.gov)
• In this case, the twins only share 50 percent of their DNA, making them no more alike than non-twin siblings. (scarymommy.com)
• And you'd be hard-pressed to find a person who isn't guilty of accidentally mixing up siblings in an identical twin set. (bestlifeonline.com)

Diamniotic2

• In a di/di pregnancy (more scientifically referred to as a dichorionic diamniotic pregnancy) the twins each have their own chorionic and amniotic sacs. (healthline.com)
• Dizygotic twins are always dichorionic and diamniotic, where each twin has its own chorionic and amniotic sac. (intechopen.com)

Types of twins5

• The two types of twins are classified as monozygotic and dizygotic. (medlineplus.gov)
• There are two types of twins: monozygotic (identical) and dizygotic (fraternal). (kidshealth.org)
• Unless you are a twin or have given birth to twins, you may be confused about the different types of twins and what their genetic makeups are. (healthline.com)
• What are the "main" types of twins? (scarymommy.com)
• Knowing how these types of twins are formed serves as an important basis for the understanding of semi-identical twins. (scarymommy.com)

Genes13

• It is possible that genes involved in sticking cells together (cell adhesion) may contribute to MZ twinning, although this hypothesis has not been confirmed. (medlineplus.gov)
• Few specific genes in humans have been definitively linked with hyperovulation or an increased probability of DZ twinning. (medlineplus.gov)
• The first large-scale study of its kind in twins has turned up evidence that we inherit instructions for the turning on and off of genes via mechanisms beyond the traditional sequence differences in the genetic code. (nih.gov)
• Even though they share the same genes, identical twins often differ in important ways. (nih.gov)
• By contrast, Petronis and colleagues suggest that fraternal twins also may differ more because they have more divergent sets of instructions for turning genes on and off. (nih.gov)
• Although studies with adult twins on SARS-CoV-2 infection are rare so far, the fact that there is a genetic component associated with the highly variable clinical outcomes of COVID-19 has already been highlighted in recent studies investigating potential candidate genes and polymorphisms. (frontiersin.org)
• However, gene-environment interactions may still be a source of differences between twins, and the search for candidate genes remains crucial on the road to personalized medicine. (frontiersin.org)
• Dizygotic twins (DZ), who grow up together, are equally exposed to a comparable influence of environmental factors, but in contrast to MZ share only about 50% of their genes ( 3 ). (frontiersin.org)
• Fraternal twins may be the same gender, they may have many of the same characteristics, but also may be very different from each other and, in fact, share half of their genes just like their sisters and brothers. (genome.gov)
• If there is overlap in genes for two traits it is expected that the cross-twin cross-trait correlation will be higher in monozygotic (MZ) twins than in dizygotic (DZ) twins for these traits. (ersjournals.com)
• Though rare, these sesquizygotic twins are the result of two sperm fertilizing a single egg, then the egg splits-so they have 100 percent match of their mother's genes and some odd percentage match of their father's. (bestlifeonline.com)
• In twin studies, researchers compare identical (monozygotic) twins, who share almost all of their genes, with fraternal (dizygotic) twins, who share about half of their genes. (nih.gov)
• Thus if identical twins show more similarity on a given trait compared to fraternal twins, it suggests that genes significantly influence that trait. (nih.gov)

Familial2

• Machin G. Familial monozygotic twinning: a report of seven pedigrees. (medlineplus.gov)
• 14. A familial case of Kikuchi-Fujimoto disease in dizygotic twins. (nih.gov)

Heritability6

• Traditional notions of heritability hold that fraternal twins differ more than identical twins simply because the former don't share the same DNA , the fixed sequence of letters in our genetic code. (nih.gov)
• The heritability was 0.57 (95% CI, 0.45-0.69) amongst male twins, and 0.38 (0.26-0.50) amongst female twins. (nih.gov)
• Twin and family studies reveal strong environmental and weaker genetic cues explaining heritability of eosinophilic esophagitis. (nih.gov)
• A twin study would help determine whether this assumption is reasonable by allowing an estimate of ALS heritability. (bmj.com)
• The British Motor Neuron Disease (MND) Twin Study 14 made a start on this process by reporting the likely range in which the ALS heritability value would lie: 0.38 to 0.85. (bmj.com)
• 16 We have analysed these two new data sets with the existing data used for the British MND Twin Study, independently but simultaneously in a meta-analysis framework, to generate for the first time an estimate of ALS heritability. (bmj.com)

Traits1

• Study One: Substantial genetic overlap between Schizotypy and Neuroticism: A Twin Study Schizotypy can be seen as a cluster of personality traits, phenomologically similar to, yet expressed in an attenuated form compared to the full-blown features of schizophrenia spectrum disorders. (uni-muenchen.de)

Eggs7

• Fraternal twins (also called dizygotic twins) result from the fertilization of two separate eggs with two different sperm during the same pregnancy. (genome.gov)
• And the difference between fraternal and identical twins is that fraternal twins derive from two different eggs. (genome.gov)
• It's important to recognize that the difference between fraternal twins and monozygotic, or identical twins, is that monozygotic twins result from the fertilization of a single egg with a single sperm and then during the embryonic development, or during the cell splits, those massive eggs split into two individuals, which later develop into two offspring. (genome.gov)
• Fraternal twins are also called dizygotic twins, because they come from two different eggs. (healthline.com)
• With dizygotic twins, two separate sperm fertilize two separate eggs. (scarymommy.com)
• Mothers are more likely to have twins if they have the genetic trait of releasing two eggs during their period. (scarymommy.com)
• for fraternal twins, two eggs are fertilized. (bestlifeonline.com)

Prevalence2

• The prevalence of EH by teeth was 21% in monozygotic twins (MZ), 22% in dizygotic twins (DZ), and 15% in singleton controls. (edu.au)
• Studies of the prevalence of autoimmune disease in monozygotic twins show that genetic as well as environmental factors (such as infection) are necessary for the disease to develop ( 6 ). (cdc.gov)

Researchers5

• Since at least 1874, twin researchers have assumed that dizygotic twins were equally likely to be SS or OS (later formalized as Weinberg's Differential Rule). (medscape.com)
• To explain how DZ twinning can run in families, researchers have looked for genetic factors that increase the chance of hyperovulation. (medlineplus.gov)
• To pinpoint such divergences, the researchers searched for how often twins shared a common type of epigenetic mark created when a molecule called a methyl group attaches to a certain part of DNA. (nih.gov)
• Semi-identical twins are so rare that some researchers don't expect another set will ever be confirmed. (scarymommy.com)
• In a landmark 1990 study published in the journal Science , researchers studied more than 100 sets of twins who grew up apart. (bestlifeonline.com)

Zygosity2

• Before modern genetic knowledge and technology, it was impossible to determine the zygosity of same-sex (SS) twins with certainty, and it was therefore difficult to estimate accurately the population incidence of monozygotic (MZ) and dizygotic (DZ) twins. (medscape.com)
• Twin pregnancies are categorized according to three factors, zygosity, chorionicity and amnionicity. (intechopen.com)

Genomes2

• As a result, identical twins share the same genomes and are always the same sex. (genome.gov)
• Monozygotic twins share 100 percent of their genomes, dizygotic 50 percent, and sesquizygotic share some percentage in the middle. (bestlifeonline.com)

Methylation2

• Cells from cheek swabs revealed that patterns of methylation were more similar in identical than fraternal twins. (nih.gov)
• Characterizing genetic and environmental influences on variable DNA methylation using monozygotic and dizygotic twins. (duke.edu)

Genome2

• A genome wide linkage scan for dizygotic twinning in 525 families of mothers of dizygotic twins. (medlineplus.gov)
• But even in identical twins, epigenetic differences were commonplace throughout the genome. (nih.gov)

Type of twins3

• The likelihood of conceiving twins is a complex trait, meaning that it is affected by multiple genetic and environmental factors, depending on the type of twins. (medlineplus.gov)
• This type of twins is much more common. (kidshealth.org)
• The type of twins (fraternal or identical) and the timing of their development affects whether the babies shared or had their own separate chorionic and amniotic sacs . (healthline.com)

Fraternal or identical1

• Sometimes health care professionals identify same-sex twins as fraternal or identical based on ultrasound findings or by examining the membranes at the time of delivery. (healthychildren.org)

1,000 births4

• MZ twins occur in 3 to 4 per 1,000 births worldwide. (medlineplus.gov)
• While the international rate of twin birth is 13.1 per 1,000 births, the average across the middle of Africa jumps to over 18 per 1,000. (bestlifeonline.com)
• The town of Igbo-Ora, Nigeria, was long considered to be the city with the highest rate of twins, with the BBC citing as many as 45 to 50 twins for every 1,000 births there in the years between 1972 and 1982. (bestlifeonline.com)
• In the more recent PLOS One study, the title of most twins in Africa goes to a small country called The Republic of Benin, which sees 27.9 twins per 1,000 births! (bestlifeonline.com)

Sesquizygotic twins1

• In the case of the Brisbane sesquizygotic twins, the fertilized egg appears to have equally divided up the three sets of chromosomes into groups of cells which then split into two, creating the twins," Dr. Michael Gabbett, clinical geneticist and diagnostic genomics course coordinator at Queensland University, explained in a press release . (scarymommy.com)

Placenta4

• In MCDADZ twin, vascular anastomosis occurs by sharing the placenta, then twin-twin transfusion syndrome or the confusion in blood typing or genetic test due to blood chimerism can occur. (e-kmj.org)
• Well, if two twins share a chorion, they'll share one placenta. (healthline.com)
• Twin-to-twin transfusion syndrome (TTTS): TTTS can occur in identical twin pregnancies that share a placenta. (blogarama.com)
• Occasionally a family is told that their twins are fraternal based on placenta findings, when they are in fact identical. (healthychildren.org)

Fertility3

• Identification of Common Genetic Variants Influencing Spontaneous Dizygotic Twinning and Female Fertility. (medlineplus.gov)
• But with twin births on the rise due to advances in fertility treatments , this rare type of twinning could become less of a mystery in the near future. (scarymommy.com)
• After all, if you're trying to conceive (either naturally or via fertility treatments), there's a chance you'll wind up a mother of twins. (scarymommy.com)

20192

• In fact, only the second confirmed case of semi-identical twins was reported in 2019 by the New England Journal of Medicine . (scarymommy.com)
• In the case of the twins reported in 2019 (who were born in 2014), they were found to be "100 percent identical on their mother's side and 78 percent identical on their father's side. (scarymommy.com)

Sexes2

• A couple of theoretical reasons cast doubt on the second assumption-the independent determination of sexes in DZ twins-and thus the validity of WDR itself. (medscape.com)
• Such twins are genetically distinct and can be of different sexes. (nih.gov)

Registry4

• All twins age 55 and older in the nationwide Swedish Twin Registry were invited to participate. (elsevierpure.com)
• We have therefore collected twin data from two further sources: the Swedish Twin Registry 15 and the King's College Hospital Motor Neuron Disease Clinic Register. (bmj.com)
• The Washington State Twin Registry suggests that mirror twins can traced back to the splitting of the fertilized egg in the womb: When the egg is split, it may already have a clear left and right side, leading to mirroring. (bestlifeonline.com)
• The team took blood samples from 210 healthy twins, ranging in age from 8 to 82, who were part of a twin registry. (nih.gov)

Humans2

• Monden C, Pison G, Smits J. Twin Peaks: more twinning in humans than ever before. (medlineplus.gov)
• While twins may confuse us humans, canines can sniff out their differences. (bestlifeonline.com)

Probability1

• The probability of dying from CHD given that one's twin partner already has died from CHD decreased with increasing age, particularly amongst males. (nih.gov)

Genetic and environmental4

• The study of enamel hypoplasia (EH) and opacity in twins provides insights into the contribution of genetic and environmental factors in the expression of enamel defects. (edu.au)
• Twin studies are an important methodological tool for recording genetic and environmental influences. (frontiersin.org)
• Twin and family studies are widely used to estimate genetic and environmental contributions to atopic disease 5 , 6 . (ersjournals.com)
• The multivariate classical twin design can help to estimate the degree to which the same genetic and environmental factors influence different intermediate phenotypes 7 . (ersjournals.com)

Factors8

• Research suggests that most cases of MZ twinning are not caused by genetic factors. (medlineplus.gov)
• Other factors known to influence the chance of having DZ twins include the mother's age, ethnic background, diet, body type, and number of other children. (medlineplus.gov)
• A brief overview of the factors that influence twinning is available from the UK National Health Service. (medlineplus.gov)
• Factors contributing to increase EH in twins were neonatal complications including intubation. (edu.au)
• For example, if one identical twin develops schizophrenia , the other twin is spared the illness in about half of cases - despite evidence that at least 70 percent of the risk for the disorder is traceable to genetic factors. (nih.gov)
• Monozygotic twins (MZ) have an almost identical genetic constitution and are also exposed to a comparable influence of environmental factors when they grow up together. (frontiersin.org)
• Different delivery options: Depending on various factors such as the position of the babies and any potential complications, a twin pregnancy may result in a vaginal delivery or a cesarean section (C-section). (blogarama.com)
• 5) The etiology of onychophagia is unknown although genetic factors may be at play (it is more common in monozygotic than dizygotic twins). (aad.org)

Suggests2

• However, recent research on the sex-specific nature of breastmilk suggests that OS twins might be at a developmental disadvantage relative to SS twins. (medscape.com)
• The greater epigenetic divergences in fraternal twins suggests that some of our epigenome is inherited, since they developed from separate cells. (nih.gov)

Pregnancies10

• Twin pregnancies are one of the most magical occurrences in nature. (scarymommy.com)
• It is important to note that false negatives are not exclusive to Twin Pregnancies and can occur in any type of pregnancy. (blogarama.com)
• Elevated hCG levels: Twin Pregnancies may result in higher levels of human chorionic gonadotropin (hCG), a hormone detected in pregnancy tests. (blogarama.com)
• Excessive morning sickness: Twin pregnancies are often associated with more severe morning sickness (nausea and vomiting) due to higher hormone levels. (blogarama.com)
• Higher risk of complications: Twin pregnancies have a higher risk of certain complications, such as preterm birth, gestational diabetes, preeclampsia, placental abnormalities, and fetal growth restriction. (blogarama.com)
• More intense pregnancy symptoms: Twin pregnancies often come with more pronounced pregnancy symptoms due to higher hormone levels. (blogarama.com)
• Preeclampsia: Twin pregnancies have a higher risk of developing preeclampsia, a condition characterized by high blood pressure and organ damage. (blogarama.com)
• Monozygotic twins account for 1/3 of twin pregnancies and show higher morbidity and mortality. (intechopen.com)
• Morbitidies are shown notable decreasing tendency depending on improving of high risk obstetric and neonatal care, however is still discussed the optimum labour management in twin pregnancies Vaginal delivery in twin pregnancies is possible when both have cephalic presentation and in the late weeks of pregnancy during which the risks of prematurity are minimized. (intechopen.com)
• The aim of this review was the assessment and evaluation the impact of the labour modus and timing of termination of twin pregnancies due to rise of their occurrence based on scientific aspects of the new published literature on perinatal outcome. (intechopen.com)

Environmental influences1

• MZ twins share a more similar environment than DZ twins, so the difference between MZ and DZ may not be genetic at all, but instead environmental influences. (brainscape.com)

Pregnancy13

• This may mean a twin pregnancy, triplet pregnancy, or more. (kidshealth.org)
• A typical, single pregnancy lasts about 40 weeks, but a twin pregnancy often lasts between 35 to 37 weeks. (kidshealth.org)
• When someone talks about twins they are referring to two babies that develop during the same pregnancy, but this can happen in many different ways. (healthline.com)
• Is it possible for Twins to cause a pregnancy test to show a negative result when a person is actually pregnant? (blogarama.com)
• In some cases, the hormone levels produced by a twin pregnancy may not be detected by the pregnancy test, leading to a false negative result. (blogarama.com)
• What are the signs and symptoms of a twin pregnancy? (blogarama.com)
• Rapid weight gain: Women carrying twins often experience more significant weight gain early in pregnancy due to the increased size and number of the developing babies. (blogarama.com)
• How does a twin pregnancy differ from a singleton pregnancy? (blogarama.com)
• Increased weight gain and size: Women carrying twins tend to experience more rapid weight gain and a larger increase in overall size compared to those with a singleton pregnancy. (blogarama.com)
• What are the potential risks and complications associated with a twin pregnancy? (blogarama.com)
• A twin pregnancy carries certain risks and complications that are important to be aware of. (blogarama.com)
• Preterm birth: Twins are more likely to be born prematurely, meaning before the 37th week of pregnancy. (blogarama.com)
• Chorionicity and amnionicity determine the risks of twin pregnancy. (intechopen.com)

Occur3

• Monozygotic (MZ) twins, also called identical twins, occur when a single egg cell is fertilized by a single sperm cell. (medlineplus.gov)
• Dizygotic (DZ) twins, also called fraternal twins, occur when two egg cells are each fertilized by a different sperm cell in the same menstrual cycle. (medlineplus.gov)
• Girl-boy twins occur when one X egg is fertilized with an X sperm, and a Y sperm fertilizes the other X egg. (healthychildren.org)

Mother's1

• Somewhere between fraternal and identical, these twins share 100 percent of DNA on their mother's side, but only about 50 percent on their father's side. (scarymommy.com)

Identical or fraternal3

• The best way to determine if twins are identical or fraternal is by examining each child's DNA. (healthychildren.org)
• There are a few commercial laboratories that, for a fee, will send families DNA collection kits to determine if the twins are identical or fraternal. (healthychildren.org)
• We considered for our study twin persons, male or female, identical or fraternal, within which one or both have transitioned from female to male (FtM) or male to female (MtF). (hawaii.edu)

Amniotic sac1

• Identical, or monozygotic, twins may or may not share the same amniotic sac, depending on how early the single fertilized egg divides into 2. (healthychildren.org)

Incidence1

• There is a higher incidence of twins across Central Africa than any other area in the world, according to research published in 2011 in PLOS One . (bestlifeonline.com)

Differences1

• Other times, a family may see the minor differences in identical twins and declare the twins fraternal based on these differences in appearance. (healthychildren.org)

19991

• With a background in studying the relationship of twinning and homosexuality (Whitam, Diamond, & Martin, 1993) and uncovering the twins involved in the John/Joan case (M. Diamond & Sigmundson, 1997) as well as having reported on conjoined twins (M. Diamond, 1999) all due to a long term interest in sexual development (M. Diamond, 1965, 2006, 2011a), immediately piqued curiosity and initiated a search as to previous findings. (hawaii.edu)

Difference between identical1

• Dogs can tell the difference between identical twins. (bestlifeonline.com)

Assumption2

• Unless the twins are different genders , the assumption at birth may just be that they're identical. (scarymommy.com)
• The equal environment assumption of the classic twin study might not hold for epigenetic aging. (sens.org)

Chromosomes2

• These twins are genetically identical, with the same chromosomes and similar physical characteristics. (kidshealth.org)
• Because identical twins come from the same egg/sperm, their chromosomes will be identical, which means they will be the same sex and have the same genetic characteristics (e.g., hair and eye color). (healthline.com)

Sperm5

• In contrast, identical twins (or monozygotic twins) result from the fertilization of a single egg by a single sperm, with the fertilized egg then splitting into two. (genome.gov)
• Identical twins are created when one egg and sperm meet like normal. (healthline.com)
• With monozygotic twins, a single egg is fertilized by two different sperm. (scarymommy.com)
• Okay, so we have a basic grasp of what happens to create semi-identical twins: A single egg splits after being fertilized by two sperm. (scarymommy.com)
• Well, with half-identical twins, a single egg splits and then each of its halves meets and gets fertilized by sperm. (scarymommy.com)

Theoretical2

• We performed a one-sample t -test of the proportion of SS dizygotic twins against the theoretical null value of 0.5022. (medscape.com)
• In order to achieve a better comprehension of ECCI contrasts of twin-boundary and stacking fault, an original theoretical approach based on the dynamical diffraction theory is used. (mdpi.com)

Equally1

• therefore, DZ twins would be equally likely to be SS as OS. (medscape.com)

Transfusion syndrome2

• Although there was no twin-twin transfusion syndrome or disconcordant blood-typing in our twins, genetic counseling and long-term follow up is needed for possible confusion in laboratory test due to persistent blood chimerism in the future. (e-kmj.org)
• 선천성 혈액 한정키메라증은 이란성 쌍둥이(dizygotic twin)에서 태아-태아혈액 사이의 교환으로 인해 생기는 쌍둥이 혈액한정 키메라증이 대표적이며, 혈액형이나 유전검사에서 우연히 발견되거나 쌍둥이간 수혈증후군(Twin-twin transfusion syndrome)으로 발견되는 경우가 있다. (e-kmj.org)

Independently1

• When twins participate in an RCT, they can be randomised to the same treatment group (a form of cluster randomisation), or one twin can be assigned to the intervention group and the other to the control group (a "co-twin intervention" design), or randomised independently in which case they may can be randomised to the same or different treatment groups. (twins.org.au)

Share3

• Because twins share their parents and parental condition, they are more likely to be SS-either both male if the parental condition is good or both female if the parental condition is poor. (medscape.com)
• Like the chorion, twins can either share an amnion or have one all of their own. (healthline.com)
• Not only are your babies born with a built-in best friend, but they will also share a special connection with that BFF for the rest of their lives - twins have support before they even get out of the womb. (scarymommy.com)

Scientific1

• About 25 percent of identical twins are mirror images of one another, according a 2012 article in Scientific American . (bestlifeonline.com)

Concordant1

• Twins were studied that are concordant or discordant for gender identity status in order to provide clarification of this issue. (hawaii.edu)

Data3

• Twin type (monozygotic versus dizygotic) was classified by the mother, not by DNA typing, although supplementary data suggest that misclassification was negligible and supplementary analysis shows that potential misclassifications do not change our main conclusions. (medscape.com)
• For example, Fellman and Eriksson (2006) analyzed twin data from Sweden and Finland, and concluded that 'WDR is robust and, despite its simplicity, gives reliable results when large national birth registers are considered' (p. 254). (medscape.com)
• Healthy adults' data ( N = 953 [41% twins]) were analysed from the PREDICT dietary intervention trial. (springer.com)

Study9

• The study sample consisted of 88 twin children and 40 singletons aged 2-4 years of age. (edu.au)
• The study checked for the telltale marks at 6,000 chromosomal locations in cells from three different types of tissue - blood, cheek and gut - in 100 sets of identical and fraternal twins. (nih.gov)
• This is the first study of adult monozygotic (MZ) and dizygotic (DZ) twins concordantly affected by SARS-CoV-2 infection to estimate variances explained by genetic, shared, and individual environmental components of both somatic and psychological symptoms following SARS-CoV-2 infection. (frontiersin.org)
• The cohort drawn for the present study includes 20 966 twins born in Sweden between 1886 and 1925 where both twins within a pair still lived within the country in 1961. (nih.gov)
• The families participating in the asthma study were a sample of a larger number of Dutch twin families who participated in the Netherlands Twin Register (NTR), an ongoing survey study of health-related behaviour 8 - 10 . (ersjournals.com)
• In a 2011 study published in the journal PLOS One , German shepherd police dogs were presented with the scents of identical twins. (bestlifeonline.com)
• A letter from a set of identical twin sisters alerted me that one, but not the other, would be transitioning to live as a man and asking if they might be useful in a study of transsexuality. (hawaii.edu)
• It became clear that transsexuality among twins had, indeed, been reported but that no directed study of the phenomenon had been done. (hawaii.edu)
• We also advertised our desire to study relevant twins by posting our request for subjects on different Internet websites (see Appendix). (hawaii.edu)

Methodological1

• Trials that include twins pose practical, methodological and ethical difficulties, but these can be overcome with careful design and implementation. (twins.org.au)

Sets of twins1

• The search yielded 43 sets of twins from available sources (Tables 1 and 2). (hawaii.edu)

Pair of twins2

• If you've found out you're having twins (or just recently met a family with a pair of twins), you may wonder, how did this happen? (healthline.com)
• Who among us hasn't been fascinated by the connection between a pair of twins , especially their ability to communicate without saying a word? (bestlifeonline.com)

Report3

• We report dizygotic twins with HGPPS that had absence of conjugate horizontal eye movements combined with divergent strabismus and synergistic divergence. (nih.gov)
• Authors report a case of MCDADZ twin who showed blood chimerism detected by karyotyping and chromosome microarray. (e-kmj.org)
• Though the dogs were already trained to track down individual scents, according to the report, they were able to pick out twins "even if they live in the same household and eat the same food," two things that make up our own personal perfumes. (bestlifeonline.com)