Two years later, a separate team showed 8 the opposite: that inactivating a gene called. Dmrt1 could turn adult testicular cells into ovarian ones. That was the big shock, the fact that it was going on post-natally, says Vincent Harley, a geneticist who studies gonad.These discoveries do not sit well in a world in which sex is still defined in binary terms. Few legal systems allow for any ambiguity in biological sex, and a person's legal rights and social status can be heavily influenced by whether their birth certificate.Illustration by Jonny Wan As a clinical geneticist, Paul James is accustomed to discussing some of the most delicate issues with his patients. But in early 2010, he found himself having a particularly awkward conversation about sex.IOS app Android app More.Parents of children with these kinds of conditions known as intersex conditions, or differences or disorders of sex development (DSDs) often face difficult decisions about whether to bring up their child as a boy or a girl.LISTEN Claire Ainsworth discusses the spectrum between male and female. You may need a more recent browser or to install the latest version of the Adobe Flash Plugin. Sex can be much more complicated than it at first seems.Some studies even suggest that the sex of each cell drives its behaviour, through a complicated network of molecular interactions. I think there's much greater diversity within male or female, and there is certainly an area of overlap where some people can't easily define themselves.Ovotesticular DSD XX, XY or mix of both Both ovarian and testicular tissue Ambiguous Rare reports of predominantly XY people conceiving and bearing a healthy child. 46,XX testicular DSD XX Small testes Male external genitals Usually caused by presence of male sex-determining gene SRY.What's more, new technologies in DNA extra marital affair dating Naughtydating sequencing and cell biology are revealing that almost everyone is, to varying degrees, a patchwork of genetically distinct cells, some with a sex that might not match that of the rest of their body.For many years, scientists believed that female development was the default programme, and that male development was actively switched on by the presence of a particular gene on the Y chromosome. In 1990, researchers made headlines when they uncovered the identity of this gene 3.People with CAIS have Y chromosomes and internal testes, but their external genitalia are female, and they develop as females at puberty. Conditions such as these meet the medical definition of DSDs, in which an individual's anatomical sex seems to be at odds with their.But they are rare affecting about 1 in 4,500 people 9. Some researchers now say that the definition should be widened to include subtle variations of anatomy such as mild hypospadias, in which a man's urethral opening is on the underside of his penis rather.