The world's largest sperm bank is refusing donations from men who are redheaded because there is just not enough demand for their sperm.

Cryos, a sperm banking network based in Denmark, which ships semen to 65 countries, has reached such a level of popularity and demand that they have become more selective about their sperm donors.

"There are too many redheads in relation to demand," director Ole Schou explained to Danish newspaperEkstrabladet.

"I do not think you choose a redhead, unless the partner - for example, the sterile male - has red hair or because the lone woman has a preference for redheads."

"And that's perhaps not so many, especially in the latter case."

The only reliable demand for sperm from redheaded donors is in Ireland.

Mr Schou said the most in-demand sperm was from donors with brown hair and brown eyes due to the high demand from Mediterranean countries.

Cryos was established in 1987 in Aarhus, Denmark, by the founder, Ole Schou. Ole Schou had for a long time had an idea of creating a sperm bank.

The office and laboratory were initially established as a service for men who were going to have a vasectomy and for cancer patients who needed to have their sperm frozen before chemotherapy or radiation.

In 1990 the donor program was established and the first portions of donor semen were released and delivered after the quarantine in April 1991. Very quickly demands increased. Initially, clinics in Denmark started receiving semen from Cryos, followed by clinics in Norway, Finland, Iceland, UK, Greece, Germany, Italy, Switzerland, Belgium, etc. The clinics were particularly satisfied with the high quality of semen resulting in a high pregnancy outcome and the professional service with immediate supply from a relatively high selection of different donors.

Whilst considered highly controversial, the development of sperm banks have led to enabling a people to have greater control over their reproductive lives. By providing sperm from donors who are checked and screened, thousands of women every year are able to bear their own children in circumstances where this might not be possible.

Sperm banks sometimes enable a woman to choose the sex of her child, enabling even greater control over the way families are planned. Sperm banks increasingly adopt a less formal approach to the provision of their services thereby enabling people to take a relaxed approach to their own individual requirements.

However, in many parts of the world sperm banks are not allowed to be established or to operate. Sperm banks do not provide a cure for infertility in that it is the sperm donor who reproduces himself, not a partner of the recipient woman.

As we all know by now, most societies are built upon the family model and sperm banks may be seen as a threat to this, particularly where a sperm bank makes its services available to unmarried women.

There is an acute shortage of sperm donors in many parts of the world and there is obvious pressure from many quarters for donor sperm from those willing and able to provide it to be made available as safely and as freely as possible.