1876. Klebs had maintained that a person’s gonads determined sex. In cases of ambiguous gender, you looked at the gonadal tissue under the microscope. If it was testicular, the person was male; if ovarian, female. The hunch here was that a person’s gonads would orchestrate sexual development, especially at puberty. But it turned out to be more complicated than that. Klebs had begun the task, but the world had to wait another hundred years for Peter Luce to come along and finish it.
