infertility human 7 Male 5 Female 4 Humans 4 female 4 male 4 Animals 3 article 3 clinical article 3 human cell 3 nonhuman 3 pregnancy 3 priority journal 3 Adult 2 Infertility, Male 2 Ovary 2 Reproduction 2 Spermatozoa 2 Testis 2 adult 2 animal 2 controlled study 2 endocrine function 2 fertility 2 fertilization 2 fertilization in vitro 2 genetic analysis 2 gonadotropin 2 gonadotropin release 2