The reproductive system of monkeys is a series of organs responsible for producing gametes, engaging in sexual intercourse and producing offspring. This system includes the male and female gonads, the external and internal genitalia, and the uterus and fallopian tubes of the female.
The reproductive system of monkeys is similar in structure to that of other primates and mammals in general, though specific species may posses unique variations. In the male, the gonads are referred to as testes and produce the male gamete cells known as sperm.
The external genitalia of the male consists primarily of the penis, a tubular organ used to introduce sperm into a female during sexual intercourse through the female's vagina, an external opening leading to the uterus of the female. The gonads of female monkeys are referred to as ovaries. These organs are responsible for producing egg cells that combine with sperm to produce fertilized embryos that implant in the lining of the uterus and grow into new individuals.
Like female humans and apes, female monkeys undergo a periodic menstrual cycle where the animal releases eggs into the fallopian tube and uterus for fertilization. If fertilization does not occur, the lining of the uterus is discarded and expelled through the vagina. The duration of fertility and the length of the menstrual cycle vary from species to species, though cycles lasting approximately a month are common.