frozen. A female chooses a donor and notifies the agency when she requires donations. The agency notifies the donor who must supply his sperm on the appropriate days nominated by the recipient. The agency will usually provide the sperm donor with a male collection kit usually including a collection condom and a container for shipping the sperm. This is collected and delivered by courier and the female uses the donor's sperm to inseminate herself, typically without medical supervision. This process preserves anonymity and enables a donor to produce sperm in the privacy of his own home. A donor will generally produce samples once or twice during a recipient's fertile period, but a second sample each time may not have the same fecundity of the first sample because it is produced too soon after the first one. Pregnancy rates by this method vary more than those achieved by sperm banks or fertility clinics. Transit times may vary and these have a significant effect on sperm viability so that if a donor is not located near to a recipient female the sperm may deteriorate. However, the use of fresh, as opposed to frozen, semen will mean that a sample has a greater fecundity and can produce higher pregnancy rates. Sperm agencies may impose limits on the number of pregnancies achieved from each donor, but in practice this is more difficult to achieve than for sperm banks where the whole process may be more regulated. Most sperm donors only donate for a limited period, however, and since sperm supplied by a sperm agency is not processed into a number of different vials, there is a practical limit on the number of pregnancies which are usually produced in this way. A sperm agency will, for the same reason, be less likely than a sperm bank to enable a female to have subsequent children by the same donor. Sperm agencies are largely unregulated and, because the sperm is not quarantined, may carry sexually transmitted diseases. This lack of regulation has led to authorities in some jurisdictions bringing legal action against sperm agencies. Agencies typically insist on STI testing for donors, but such tests cannot detect recent infections. Donors providing sperm in this way may not be protected by laws which apply to donations through a sperm bank or fertility clinic and will, if traced, be regarded as the legal father of each child produced. Private