Why mammalian gametes don't mix.
D000818:Animals; D005260:Female; D005306:Fertilization; D006801:Humans; D006824:Hybridization, Genetic; D008297:Male; D010063:Ovum / Q000502:physiology*; D011247:Pregnancy; D013045:Species Specificity; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000502:physiology*