If my sister had balls would she be my brother?

"It depends. If your ""sister"" was born with ambiguous genitalia, but had XY chromosomes, then, yes, ""she"" would be your brother, because ""she"" would be genetically male. However, if your sister was born with ambiguous genitalia, but had XX chromosomes, she would still be your sister, because she would be genetically female. It also depends on how your sister identifies herself. She may have balls and be genetically male, but if she identifies and presents herself as female, then she would still be your sister. However, ""she"" identified and presented as a male, ""she"" would be your brother. People are born with ambiguous genitalia all the time. The only way to tell the sex of the child is to do a DNA test. Some folks are born XXY or XYY, or even XXYY. Some folks just don't feel like they were born the right gender, so they psychologically identify as the opposite gender. Self-identity is the first determination of gender. Chromosomes are the second. Genitals are a distant third, and, considering the miracles modern surgery can render, really can not be relied on to determine sex. Didn't think this question would generate such a long response, did you?"