Pregnancy occurs as the result of the female gamete or oocyte (egg) being penetrated by the male gamete spermatozoon in a process referred to as fertilization, or more commonly known as conception. The fusion of male and female gametes usually occurs through the act of sexual intercourse. However, the advent of artificial insemination has also made achieving pregnancy possible in such cases where sexual intercourse is not potentially fertile (through choice or male/female infertility).