Number 1604 has straight black hair and brown eyes. A student nurse, he claims to be outgoing and, at times, funny.

He is also a Catholic, and used to be a good dancer. He has mild colour-blindness, and once had surgery to repair a hernia. His maternal grandmother had arthritis, his paternal grandmother diabetes.

All of which may tell you more about number 1604 than you actually want to know - unless, of course, you are planning to have his babies, and even then I'm not entirely convinced that every mother-to-be demands urinalysis first, or could recite the medical history of their partner's grandparents.

But our man is a sperm donor, one of thousands to have contributed his little bit to the Sperm Bank of California. The level of information given here, plus a little more, is free. For $15 you can get a complete medical history. For $25 they will compare your photograph with that of the donor to ensure a match. For $200 more, they will pack a sample of his semen in liquid nitrogen and send it to you by Federal Express.

But even in Berkeley and the San Francisco Bay it is not quite that free and easy. Both the not-for-profit Sperm Bank of California and California Cryobank Inc would prefer it if you got a doctor or nurse to help out, and that you gave informed consent to the transaction.

The forms don't look that arduous, though.

And what a service. The Sperm Bank of California even has a family contact list so that recipients who use the same donor can get together and swap stories about their offspring.

After some years collecting names, the bank has made its first match and two 'moms' are already busily exchanging e-mails.

None of which explains why an AltaVista search on the phrase 'sperm bank' suggests a link to the Center for the Study of Extraterrestrial Intelligence. Very X Files .

These and other sites of interest can be reached via HSJ's website at www.hsj.co.uk