When the child was born, the midwife told the expected parents, “It’s a boy!” Then a few minutes later, the midwife said, “it’s a girl, after all.”

Dora Ratjen was born on November 20, 1918. When she was in her teenage years, Ratjen began to compete in sports, strong enough to take fourth place at the 1936 Berlin Olympics in the high jump. And at the age of 20, she won a gold medal at the European Athletics Championships with a world record high jump of 1.67 meters. But the previous world record holder, Dorothy Tyler-Odam, said what everyone else thought, “she’s not a woman, she’s a man.”

On September 21, 1939, a train conductor reported that there was a man dressed as a woman in his train. Ratjen was pulled off the train and questioned by the police. He showed official papers that proved his female gender, but a doctor quickly concluded that Ratjen was a man. The German government returned Ratjen’s gold medal. As it turned out, Dora Ratjen had always thought he was a man, and eventually changed his name to Heinrich, a name he had until he passed away in 2008. In 2009, the German magazine, Der Spiegel, revealed these details about Ratjen’s sexual ambiguity.

The New York Times recently had a fantastic piece on gender ambiguity, and the humiliation a small group of athletes have had to endure to confirm their gender. The truth is, it is not clear cut as to whether certain people are definitively a man or a woman. Tests over the decades have looked at chromosomes, hormones, genetalia or reproductive organs, but there are still many cases where the gender of a given person is unclear. According to the Times, experts use the term “intersex” to describe such cases, but that may be the only thing they agree upon.

Estimates of the number of intersex people vary widely, ranging from one in 5,000 to one in 60, because experts dispute which of the myriad conditions to include and how to tally them accurately. Some intersex women, for instance, have XX chromosomes and ovaries, but because of a genetic quirk are born with ambiguous genitalia, neither male nor female. Others have XY chromosomes and undescended testes, but a mutation affecting a key enzyme makes them appear female at birth; they’re raised as girls, though at puberty, rising testosterone levels spur a deeper voice, an elongated clitoris and increased muscle mass. Still other intersex women have XY chromosomes and internal testes but appear female their whole lives, developing rounded hips and breasts, because their cells are insensitive to testosterone. They, like others, may never know their sex development was unusual, unless they’re tested for infertility — or to compete in world-class sports.

Over the decades, there have been plenty of claims of gender cheating in sport. People say, if she looks like a man, he must be a man. And due to the measures of testing in the past, women have had to go through humiliating tests, and have been shamed as cheats, Polish sprinter, Ewa Klobukowska, a case in point in the 1960s.

But there is a blurred space between men and women, an area still not fully understood by scientists or authorities – the intersex gender.