<P> The human reproductive system usually involves internal fertilization by sexual intercourse . In this process, the male inserts his penis into the female's vagina and ejaculates semen, which contains sperm . A small proportion of the sperm pass through the cervix into the uterus, and then into the Fallopian tubes for fertilization of the ovum . Only one sperm is required to fertilize the ovum . Upon successful fertilization, the fertilized ovum, or zygote, travels out of the Fallopian tube and into the uterus, where it implants in the uterine wall . This marks the beginning of gestation, better known as pregnancy, which continues for around nine months as the foetus develops . When the foetus has developed to a certain point, pregnancy is concluded with childbirth, involving labor . During labor, the muscles of the uterus contract and the cervix dilates over the course of hours, and the baby passes out of the vagina . Human infants are nearly helpless and require high levels of parental care . Infants rely on their caregivers for comfort, cleanliness, and food . Food may be provided by breastfeeding or formula feeding . </P> <P> The female reproductive system has two functions: to produce egg cells, and to protect and nourish the fetus until birth . The male reproductive system has one function: to produce and deposit sperm . Humans have a high level of sexual differentiation . In addition to differences in nearly every reproductive organ, there are numerous differences in typical secondary sex characteristics . </P> <P> The male reproductive system is a series of organs located outside the body and around the pelvis region of a male that contribute towards the reproduction process . The primary direct function of the male reproductive system is to provide the male sperm for fertilization of the ovum . </P>

The primary function of the human male reproductive system is to