Male, female, both, neither?

From NYTimes.com

The case of Caster Semenya, who has burst to prominence this season, touched off a debate over whether she should be allowed to keep her medal and, more broadly, how sports officials are supposed to discern the fuzzy biological line between male and female. Medical experts said assigning sex was hardly as easy as sizing someone up visually. Even rigorous examinations can result in ambiguous findings. Some conditions that give women male characteristics can be discovered only through intrusive physical examinations, and others require genetic analysis.

“We can get quite philosophical here — what does it mean to be male or female?” said Dr. Richard Auchus, a specialist in disorders of sexual differentiation at the University of Texas Southwestern Medical Center at Dallas.

“For 99 percent of the population it’s easy to determine,” he added. “But one percent of the population have conditions that make it not so straightforward.” …

Complicated cases are common. For example, a disorder known as congenital adrenal hyperplasia gives women excess testosterone from a source other than the testes — the adrenal glands. In mild cases, genitals may appear normal and often no one suspects the problem. Women with the disorder are allowed to compete as females.

The Bantu, a group of indigenous South African people, may be more predisposed to being hermaphrodites but they do not always have obvious male genitalia, said Dr. Maria New, an endocrinologist at Mount Sinai School of Medicine. They are genetically female yet have both testes and ovaries.

To spot the condition, doctors sometimes must do a laparoscopic exam, remove tissue from the gonads, and biopsy it, New said.

Then there is a list of rare genetic disorders that can confuse sexual identity. Some genetic males, for example, have mutations in a gene needed to form testes. Although they look like women, genetically they are men, with an X chromosome and a Y chromosome.

Davies said that the sex testing includes “chromosome testing, gynecological investigation, all manner of things, organ, X-rays, scans.” But, New said, if the tests do not include genetic ones, most of the sex disorders will be missed. Chromosomes can look perfectly normal, she said. It is the genes that are altered.