limit the overall number of pregnancies permitted from a single donor. The limitation on the number of children which a donor's sperm may give rise to is usually expressed in terms of 'families', on the expectation that children within the family are prohibited from sexual relations under incest laws. In effect, the term family means a "woman" and usually includes the donor's partner or ex-partner, so that multiple donations to the same woman are not counted in the limit. The limits usually apply within one jurisdiction, so that donor sperm may be used in other jurisdictions. Where a woman has had a child by a particular donor, there is usually no limit on the number of subsequent pregnancies which that woman may have by that same donor. There is no limit to the number of offspring which may be produced from private donors. Despite laws limiting the number of offspring, some donors may produce substantial numbers of children, particularly where they donate through different clinics, where sperm is onsold or is exported to different jurisdictions, and where countries or jurisdictions do not have a central register of donors. Sperm agencies, in contrast to sperm banks, rarely impose or enforce limits on the number of children which may be produced by a single donor partly because they are not empowered to demand a report of a pregnancy from recipients and are rarely, if ever, able to guarantee that a female may have a subsequent sibling by the donor who was the biological father of her first or earlier children. In the media, there have been reports of some donors producing anywhere from over 40 offspring to several hundred or in one case, possibly over 1000. Siblings Where a female wishes to conceive additional children by sperm donation, she will often wish to use the same donor. The advantage of having subsequent children by the same donor is that these will be full biological siblings, having the same biological father and mother. Many sperm banks offer a service of storing sperm for future pregnancies, but few will otherwise guarantee that sperm from the original donor will be available. Same sex couples looking to conceive with donor sperm also oftentimes use the same donor for multiple children in order to foster a greater biological connection between their children. In cases where both parents feel that pregnancy is appealing to them, they may decide