partial intercourse, where penetration by the donor takes place immediately before ejaculation, thus avoiding prolonged physical contact between the parties. Because NI is an essentially private matter, the extent of its popularity is unknown. However, private on-line advertisements and social media comments indicate that it is increasingly used as a means of sperm donation. Sperm bank processes A sperm donor is usually advised not to ejaculate for two to three days before providing the sample, to increase sperm count. A sperm donor produces and collects sperm at a sperm bank or clinic by masturbation or during sexual intercourse with the use of a collection condom. Preparing the sperm Sperm banks and clinics may "wash" the sperm sample to extract sperm from the rest of the material in the semen. Unwashed semen may only be used for ICI (intra-cervical) inseminations, to avoid cramping, or for IVF/ICSI procedures. It may be washed after thawing for use in IUI procedures. A cryoprotectant semen extender is added if the sperm is to be placed in frozen storage in liquid nitrogen, and the sample is then frozen in a number of vials or straws. One sample will be divided into 1–20 vials or straws depending on the quantity of the ejaculate, whether the sample is washed or unwashed, or whether it is being prepared for IVF use. Following analysis of an individual donor's sperm, straws or vials may be prepared which contain differing amounts of motile sperm post-thaw. The number of sperm in a straw prepared for IVF use, for example, will be significantly less than the number of motile sperm in a straw prepared for ICI or IUI and there will therefore be more IVF straws per ejaculate. Following the necessary quarantine period, the samples are thawed and used to inseminate women through artificial insemination or other ART treatments. Medical issues Screening Sperm banks typically screen potential donors for genetic diseases, chromosomal abnormalities and sexually transmitted infections that may be transmitted through sperm. The screening procedure generally also includes a quarantine period, in which the samples are frozen and stored for at least six months after which the donor will be re-tested for sexually transmitted diseases (STIs). This is to ensure no new infections have been acquired or have developed during the period of donation. Providing the result is negative, the sperm samples can be released from quarantine and used in treatments. Children conceived