I've heard about them. They are, I think (what I can recall), called the people of 3rd sex. They are born with both the sexes due to the presence of both female and male hormones. The appearance of the external sex organ is based on what hormone (whether male or female hormone) was more. They can choose (if they want) to be either man or woman and convert to any one sex with the help of surgery after birth. But such people becomes sterile after surgery.
I have a male friend who is intersexed, but you'd never know it. His anatomy is all male and he has a very deep "radio" voice. A medical exam once revealed to him he was sterile, and he barely grows a beard. When he had a friend go through gender reassignment, he himself learned about intersex conditions and realized he had a variety of "symptoms" that matched and on a whim decided to get himself genetically tested.
Turns out his genetic structure is XXY. He's quite proud to no longer be what he described as "common garden variety heterosexual white male."