Sex selection is one of the few bioethical issues which are opposed by both progressives and conservatives. As evidence of how unnatural the practice is, its opponents cite increasingly skewed “sex ratios”. The natural ratio of girls to boys at birth is about 105, so ratios of up to 130 in parts of China are described as perverse.

However, bioethicist Timothy F. Murphy, at the University of Illinois College of Medicine at Chicago, argues in the journal Bioethics, that “the natural sex ratio cannot be a sound moral basis for prohibiting parents from selecting the sex of their children”. What he objects to is the notion that there exists a natural state of affairs which should not be changed.

“If we move away from the view that a divine, or semi-divine, or even just a superior-to-human intelligence undergirds the operations of nature as a whole, human beings are free to choose the kinds of futures that are important to us relative to the calculations we make about the options ahead.”

Furthermore, there is more ambiguity than first meets the eye about the natural sex ratio. It varies from country to country; it varies before birth and after birth. And it varies anatomically: “The presumption that people are unequivocally male or female is not true to the facts of genetic traits, intersex conditions, and transgender identities, which is another reason that we can only know the ‘natural’ sex ratio in an approximate way.”

A rough equivalence of the sexes might be socially desirable, he acknowledges, but not because it deviates from a natural state of affairs. He concludes: “By itself, the idea of nature offers no material support for opposition to the selection of children’s sex, let alone criminalization of that practice.” ~ Bioethics, Dec 13