If you look at the back girls are more rounded and blunt where as boys have a sort of lump sticking out which is where the testicles are. Underneath the two vents are close together (about 0.5cm) on a girl and about 1.5cm apart on a boy.
If you choose a unisex name it will not matter Tomsudz. Something like Cocoa or Truffle would do a boy or girl