For centuries, couples have tried to influence the sex of their children.
Italian men bit their wives' left ears during intercourse to beget daughters; Swedish men hung their pants on the right bedpost to father boys; while German woodcutters took their axes to bed and chanted:
"ruck, ruck, raid, you shall have a maid". And such efforts had a 50 per cent success rate.
But now that safe and reliable technology has been developed to allow parents to choose the sex of their children prior to conception and with little risk of failure, not just old hopes but also new fears have been raised.
This week's House of Commons Science and Technology Select Committee report on human reproductive technologies has already prompted claims that this advance will upset the balance of the sexes, increase sexism, and send us down a slippery slope that will lead to the creation of designer babies. I don't think such concerns are justified.
For sex selection to distort the gender ratio, there has to be a marked preference for children of a particular sex.
Do Britons prefer boys over girls as once they may have? No! According to a representative survey conducted in 2003, three quarters of British couples would like to have as many girls as boys. The remaining quarter say they simply do not care.
There is, of course, often a difference between what people say and what they do. But research by demographers confirms the preference for a "balanced family".
Couples with two boys and couples with two girls are more likely to have a third child than couples with one boy and one girl, suggesting that parents with children of both sexes are more content with their family composition.
The apparent desire for a balanced family is also supported by evidence from "gender clinics". Worldwide, there are already 65 fertility centres offering sex selection. Three of them are based in the UK - in London, Birmingham and Glasgow.
According to the London Gender Clinic, well over 95 per cent of couples seeking sex selection are parents of either three boys or three girls who long to have a child of the opposite sex.
Some feminists have claimed that sex selection is "the original sexist sin". This is preposterous.
It is simply untrue that all people who would like to choose the gender of their children are motivated by the sexist belief that one sex is more valuable than the other.
If this desire is based on any beliefs at all, it is rooted in the easily defensible assumption that raising a girl is different from raising a boy, but certainly not on the ridiculous idea that one sex is somehow "superior" to the other.
Then there are those who are afraid that sex selection may lead to the creation of designer babies.
Once we tolerate parents choosing the sex of their children, it is said, we are bound to tolerate parents choosing the intelligence, height or even eye colour of their children.
But this need not worry us too much, as it is perfectly possible to draw a legal line permitting some forms of selection while prohibiting others.
Thus, if selection for sex is morally acceptable, but selection for, say, intelligence is not, the former can be allowed and the latter not.
Western democracies are based on a presumption in favour of liberty. Each and every citizen has the right to live his life as he chooses, provided he does not infringe upon the rights of others.
The state may interfere only to prevent serious harm to others.
Given that sex selection does not harm anyone, there is simply no justification for depriving parents of the right to make that choice.
Edgar Dahl
Senior research fellow at the medical centre of Giessen University, Germany