Related by context. Frequent words. (Click for all words.) 42 testes 40 sperm 37 zebrafish 37 cells 36 gland 36 breast tissue 36 ovary 35 follicles 35 ovaries 34 fertilized eggs 34 estradiol 34 penises 34 tissues 34 progenitor cells 33 genetically 33 adipose tissue 33 tissue 33 amniotic fluid 33 hormone 33 spinal fluid 32 urine 32 muscle tissue 32 prostate gland 32 stem cells 31 immune cells 31 estrogen 31 hormones 31 hair follicles 31 nitric oxide 31 genes 30 uterus 30 platelets 30 genetic mutations 30 progesterone 30 gene 30 saliva 30 fetus 30 offspring 30 chromosomes 30 antibodies 29 livers 29 ejaculation 29 lymphocytes 29 chromosomal 29 embryo 29 embryos 29 tissue samples 29 mitochondria 28 embryonic cells 28 infertile 28 penis 28 fetuses 28 testosterone 28 fertilization 28 Sperm 28 eggs 27 semen 27 testicles 27 ovulation 27 cortisol 27 X chromosome 27 fertilized egg 27 Y chromosome 26 placenta 26 womb 26 liver 25 melanin 24 stress hormones 24 pancreas 24 vitro 24 frozen embryos 24 stem cell 23 blood 23 bone marrow 23 foreskin 23 wombs 23 kidneys 22 menstrual cycle 22 organs 22 reproductive 22 cord blood 22 breast milk 22 infertility 21 umbilical cord blood 21 vasectomy 21 IVF 21 transfusion 21 ovarian 21 fertility treatments 21 egg 21 fertility clinic 20 fertility 20 human embryos 19 transfusions 19 Fertility 19 kidney 18 fertility clinics 15 vitro fertilization 14 artificial insemination 14 conceiving 14 sperm donor