It's a stark and unpalatable truth that gender selection has been going on for millennia, often in the most brutal fashion and for barely rational reasons. It still occurs regardless of rarefied debates on ethics.

I subscribe to the secular, Western take on this issue. One gender or another should not be regarded as a disease, nor in a right-thinking society be regarded as a social or economic millstone for parents. Advances in genetic science should not be used to indulge the vanity of parents who want to pre-order linebackers or ballerinas; nor should they be a pretext for certain religious communities to air their ancient prejudices.

The raw science isn’t at fault, it’s just that the application is problematic. If we’re given the means to eradicate genetic diseases that cause suffering and impair quality of life, we should use them. Perhaps if technology and resources one day permit it, the hit-list of diseases should include eczema and myopia as well as cystic fibrosis and muscular dystrophy. But does it then follow that poor hand-eye coordination or a probable lifespan below 90 are genetic defects to be repaired? What if functional immortality is one day possible? Would we be tempted to accept sterility and cultural atrophy to dodge the reaper? Should governments try to engineer equal numbers of men and women in the interests of contentment?

It is far too easy for this debate to drift into the lofty terrain where genetic science mutates into science fiction. Germline gene therapy, whereby DNA is repaired before replication, remains theoretical. Somatic gene therapy, the repair of genetic disease in isolation with no prospect of propagating a corrected version, is still an experimental area. The crude truth is that genetic science can typically only cure a disease by identifying its probable occurrence, thereby allowing parents to avoid or terminate a conception.

In this way, a clinical argument can arise for certain parents to choose a gender. For example, Haemophilia is a recessive disorder linked to the X-chromosome. Women carry the disorder but have another X-chromosome to mask it. The Y-chromosome however cannot mask the defect so even though a male child can’t propagate the disease, they are likely to manifest it. If the means were available, a medical practitioner would have to advise a female carrier against having a male child if at all possible.

Yet even here, there is danger. Widely available genetic screening and awareness of its potential might see us stumbling into a new culture of eugenics. A combination of free parental choice and the preferences of employers and insurers would not only make genotypes of the wrong profile or gender less desirable than ever, it might prevent many of them being born at all.

We might come full circle and share a dilemma familiar to the peasant farmer in the Yangtze Basin. The cultural pressures acting on him and his forebears have created a warped demographic in South-East Asia whereby men outnumber women by tens of millions. The disproportion is large enough to mirror the excess of females in the countries most damaged by the two world wars.

While Bangalore leads a regional technological revolution, elsewhere in India ‘dowry deaths’ still occur. In China, it is illegal for doctors to disclose a child’s gender before birth. Where male children are culturally and economically useful and their sisters deemed a burden or a liability, parents will too often follow an old pattern. The ability to determine gender in utero is a relatively recent development, so historically infanticide has been far more common than any other form of choosing a baby’s gender.

This debate can’t be led by science, as technology only changes the means by which old prejudices are enacted. Unless positive cultural change is pursued, gender selection in all its time-honoured horror will keep happening regardless of how people in white coats, pin-stripe suits or GAP t-shirts feel about it.