More than we ever wanted to know about sex--should we be afraid to ask?
D002582:Cervix Mucus; D002869:Chromosome Aberrations / Q000209:etiology; D025063:Chromosome Disorders; D000013:Congenital Abnormalities / Q000209:etiology; D005260:Female; D005306:Fertilization; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D008297:Male; D008598:Menstruation; D010060:Ovulation; D010063:Ovum / Q000502:physiology; D011247:Pregnancy; D012744:Sex Ratio; D013997:Time Factors