OligospermiaSpermatogenesisInfertility, MaleAzoospermiaInfertilitySperm CountSpermatozoaTestisChromosomes, Human, YSperm MotilitySemen AnalysisAsthenozoospermiaSemenMesteroloneReproductive Techniques, AssistedSex Chromosome AberrationsInfertility, FemaleFertilitySperm Injections, IntracytoplasmicHydrocarbons, BrominatedReproductive TechniquesFertilization in VitroSpermatidsSex Chromosome Disorders of Sex DevelopmentSocial MarginalizationPregnancySpermatocytesSeminiferous TubulesSeminal Plasma ProteinsSertoli CellsSpermatogoniaVaricoceleHysterosalpingographySequence Tagged SitesTestosteronePregnancy RateKlinefelter SyndromeInsemination, Artificial, HomologousY ChromosomeFamily CharacteristicsEmbryo TransferOocyte DonationChromosome AberrationsSeminiferous EpitheliumSexual Dysfunctions, PsychologicalPregnancy OutcomeInsemination, ArtificialReproductive MedicineChromosome DeletionAneuploidyPregnancy, MultipleAttitudeKaryotypingCryopreservationIn Situ Hybridization, FluorescenceBlood-Testis BarrierGerm CellsMeiosisContraceptive Agents, MaleCouples TherapyOvulation InductionOocytesLeydig CellsEpididymisPolymerase Chain ReactionCryptorchidismQuestionnairesSpermatogenesis-Blocking AgentsOrgan SizePachytene StageTime FactorsFollicle Stimulating HormoneProspective StudiesSexual MaturationAntispermatogenic AgentsTesticular DiseasesMolecular Sequence DataProtaminesSperm TailSperm HeadSperm MaturationCohort StudiesSertoli Cell-Only SyndromeGene Expression Regulation, DevelopmentalMeiotic Prophase IPrevalenceAcrosomeRNA, MessengerGonadotropins