Fisher’s principle is an evolutionary argument that explains why most sexual species tend to have a stable gender ratio that approximates 1:1. The principle is that, as one gender increases in abundance, the marginal value of having offspring of the other gender increases. So any genetic predisposition to have more of one gender than the other gets balanced out. Most species exhibit this property, and historically the gender ratio of Humans at birth has been ~105:100. Males having a slight historical surplus due to our greater tendency than females to get ourselves killed; fighting wars, hunting bears, or similar. The stability innate in Fisher’s principle is elegant, and easily understood, and this is why it is celebrated as one of the greatest arguments in evolutionary theory.

In China today there are between 30 and 50 million men who will die single for the simple reason that they are surplus, there simply aren’t enough women in China for them to marry. Historically the Chinese, as with most cultures, have favoured male offspring over females; however Fisher’s principle has seen that the advantage of having female offspring has never been weakened. As people have promoted their sons, any resultant surplus has been met by greater breeding success for the pool of girls, maintaining the gender balance. The one-child policy wreaked havoc with this. Given the choice many more parents preferred sons to daughters. Orphanages began to fill with abandoned daughters, and by the early eighties the official sex ratio at birth in China had risen to 108 boys to 100 girls.

In one sense children are an investment for parents, an investment which comes to fruition in old age, when the children become the providers and care-givers for the elderly parents. In this context males are seen as preferable; historically they have been much better equipped to earn the money needed to support the parents. Daughters are somewhat of a dead-end, generally married away into a family which they would then support, replaced by wives married in to accompany sons. This system only works when there is an adequate supply of women to be wives, and in China the relative birth rate of women was falling fast during the 80s and 90s, dangerously so.

The second blow to gender balance was the advent of screening for gender using ultrasound. Although sex-specific abortions are illegal in China that has done little to close the Pandora’s box combination of the one-child policy, the possibility to effectively ‘pick’ your child’s gender, and a social pressure to have sons. By the turn of the millennium China’s sex ratio at birth had hit 120 boys to 100 girls, inflating an already wide gender gap.

This situation has posed a series of problems for both the government, and society. Within society there is now an extensive group of effectively unmarriageable men. While marriage is not necessarily the ultimate goal in life, it is something many people strive for. These men are not evenly distributed across society either. In accordance with Fisher’s principle, as women have become scarcer, their marginal value has increased and single women have a leverage that is not present in societies with healthy gender ratios. In a curiously retrograde way, it creates a twisted form of social mobility, as women are able to marry upwards, should they so chose. The losers in this are the poor, the rural, the unskilled and the unfortunate. A surplus of males is never good for a country, it can lead to unrest, and you might expect violence against women, abductions and forced marriages to become more common. There is also the human cost, with many poor men who are unable to find a wife facing an old age without a companion, without children to bring them joy or care for them. Finally there is the issue of competition between males; older men who have had more time to accumulate wealth have an advantage over younger males from comparable backgrounds, and so there is a tendency for the age difference between male and female partners to grow, as older men outcompete younger, poorer men for the few available girls. None of these outcomes are positive, and yet there are no simple solutions to easily bring the gender gap down.

Despite this there is evidence that Fisher’s principle is in effect; the increased value of daughters in such an imbalanced society is starting to be noted, and in the last few years the ratio at birth has been falling. It is now down to around 118 males to 100 females, which while still severely imbalanced, is an improvement. There are few direct interventions any government can impose to ameliorate this sort of situation. Rescinding the one-child policy offers no guarantee that people will not continue to pursue a ‘sons first’ policy, and keep abandoning or aborting daughters. There is a possibility of offering direct incentives to people producing girls, but this offers up the worrying concept of placing a value on a child’s life, when that value should be innate. It also doesn’t consider the financial burden to the country. Ultimately, the most powerful changes China could make would have to be social. Empowering women as wage earners equal to men would weaken the concept of men as providers. Offering better end-of-life care so that parents are not so dependent on children for support would have a similar range of social benefits, albeit at a cost. Fundamentally there needs to be a change to the historical patriarchal paradigm so that society sees women as equal in potential and value to males, at every level of society, not just in the educated middle and upper classes.

These changes are not simple, and China is not the only country that will find itself needing to implement them. While China’s situation is more pronounced, India and Indonesia are examples of other countries with a growing surplus of males that will need to be balanced out in the future. It is too late for the millions of surplus men in these countries, but hopefully in time, things can return to a more balanced state, for the benefit of all people living in the country.