<unk>  is the practice of a sperm bank selling or otherwise trading or passing its surplus stocks of sperm for use by another entity. The practice is subject to the laws of particular jurisdictions involved in the trade. Sperm banks routinely collect and process sperms from sperm donors which they may use either in fertility treatments or onsell or otherwise pass on to another entity. The<unk>  may be part of, or even the main business of a particular sperm bank, or may arise where a sperm bank has collected and stored more sperm than it can use within nationally set limits. In the latter case a sperm bank may onsell or export the sperm from a particular donor that it can no longer use within the jurisdiction in which it operates, for use in another jurisdiction, subject to relevant laws. In practice, wherever possible, a sperm bank will use or sell on all the samples stored from a particular donor. Sperm banks which limit the use of a donor's samples within its own jurisdiction, or to a particular number of births, will generally limit the time for which a man may donate his sperm to obtain only the number of samples they intend to use. Sperm may also be onsold for research or educational purposes, usually after the number of births from the donor concerned has reached the national legal maximum. Sperm may also be used for genetic and fertility testing, and for research into birth control.
Onselling of sperm
Spermiogenesis
Pharmacokinetics of estradiol
Pharmacokinetics of progesterone
Resumption of meiosis
Sexual reproduction
Ovulation induction
Primordial germ cell migration