Sexual intercourse

:This article is about sexual intercourse in humans and its societal implications. For biological copulation in general, see copulation.

Biology of conception

Coitus is the basic reproductive method of humans. During ejaculation, which normally accompanies the male orgasm, a series of muscular contractions delivers semen containing male gametes known as sperm cells or spermatozoa into the vault of the vagina. The subsequent route of the sperm from the vault of the vagina, is through the cervix and into the uterus, and thence into the fallopian tubes. Sperm cells can survive up to nine days in the female body. When a fertile ovum from the female is present in the fallopian tubes, the male gamete joins with the ovum resulting in fertilization and the formation of a new embryo. When a fertilized ovum reaches the uterus, it becomes implanted in the lining of the uterus known as endometrium and a pregnancy begins.

Related Topics:
Semen - Gamete - Spermatozoa - Uterus - Fallopian tube - Ovum - Fertilization - Embryo - Endometrium - Pregnancy

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Sexual intercourse should always be considered likely to result in pregnancy unless adequate contraceptive (birth control) measures are in force. Even then, pregnancy should be considered a possible outcome of the activity since no birth control measure is 100% effective. Coitus interruptus, or "withdrawal" of the penis from the vagina just before the man’s orgasm, cannot be considered an effective method of contraception and is not recommended, as the male usually releases a small amount of semen before the main ejaculation. Abstinence from heterosexual sexual intercourse and sterilization are the only 100% effective ways to avoid pregnancy. Outercourse, in which there is sexual activity without insertion, can be performed without resulting in pregnancy provided that semen does not come in contact with the vulva.

Related Topics:
Birth control - Coitus interruptus - Abstinence - Sterilization - Outercourse

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