DNA tells your body what proteins to produce. A person can have two X chromosomes and still be phenotypically male, or an X and Y chromosomes and still be phenotypically female. Not all human existence is limited to two sex chromosomes, and within those chromosomes not all of the protein production resulting from the DNA is going to be representative of what generally happens if you're identified as having that particular set of chromosomes. Some people have what looks like it could be either a ****** or a *****. Mind you, this is all precluding what influences a parent's body has during gestation.

The fact is that there is no single chromosome, no single gene, no single protein that dictates that dictate whether a person has a ***** or a ******, and some people are born with both or neither. Some people are born with a ***** or a ****** and then later start developing all of the phenotypical characteristics that are the opposite, e.g. breasts along with a ***** and a hairy chest and larger muscles along with a ******.