tubes, where they may survive for up to 6 days. If ovulation occurs and the sperm encounter an ovum in the fallopian tube, fertilization may occur. A woman may also be naturally inseminated while having penile-vaginal intercourse for pleasure without any intent to conceive. This may be unintentional as a result of the failure of a barrier or behavioural method of contraception, or may be intentional if relying on female contraceptive methods or indifferent to the possibility of pregnancy. In most cultures, insemination by a male through sexual intercourse, whether the woman's husband, normal sex partner or not, is subject to social and sexual inhibitions and taboos, and has legal, moral and interpersonal implications. The term is also used in the context of third-party insemination, where a male who is not the woman's usual sexual partner (i.e., a sperm donor) fathers a child for the woman by providing his sperm through sexual intercourse rather than by providing his sperm for it to be used to produce a pregnancy in the woman by artificial means. The incidence of natural insemination by a sperm donor is usually a private matter, and may also carry greater health risks than where sperm has been processed by a fertility center. Advocates claim natural insemination generates higher pregnancy rates and a more 'natural' conception which does not involve the intervention and intrusion of third parties. However, it has not been medically proven that natural insemination has an increased chance of pregnancy. Additionally, conceiving through natural insemination is considered a natural process, so the father may be liable for child support and have custody and other rights of the child. The law usually draws a distinction between a man fathering a child by natural means, and a man who provides his sperm for it to be used to father a child by artificial means (i.e. by artificial insemination). Artificial insemination Artificial insemination is the introduction of sperm into the reproductive tract of a female by means other than sexual intercourse for the purpose of impregnating or fertilizing the female. In humans, artificial insemination may be used when a woman or her normal sex partner cannot, for any of a number of reasons, conceive by natural means. A number of artificial insemination strategies are available, including intracervical insemination (ICI) and intrauterine insemination (IUI). Compared with natural insemination, artificial insemination may be more invasive, and may require professional assistance