Sexual intercourse is the physical act of sex between two people. the physical activity of two people having sex with each other. or coitus or copulation Act in which the male reproductive organ enters the female reproductive tract (see reproductive system). Various sexual activities (foreplay) lead to physiological changes that progress to orgasm (climax) and resolution (see sexual response). If it is completed, semen passes from the male into the female's body. If conditions favour fertilization, a sperm joins with an egg, and pregnancy begins (see fertility; reproduction); contraception can prevent this. Intercourse with an unwilling female is rape. See also reproductive behaviour; safe sex; sexuality, human; sexually transmitted disease
the act of sexual procreation between a man and a woman; the man's penis is inserted into the woman's vagina and excited until orgasm and ejaculation occur