Female Spartan in Halo: Reach. This caused by a lag and is not a hack. But it shows that male and female Spartans have physical differences. Unlike Halo 3 they actually show what they would really look like. it's still not clear wether its just the body for the character Kat or if you will actually be able to play as a female AND have physical differences.
I can tell you now that i will play as a spartan girl!