What do you think about this?

So my housemate says that if a black man and white woman have a child....their offspring is considered a different race. But then he says that genetic markers can't prove the race of a person.

Do you think that there's such thing as different kinds of "race"? Or is there just the "human race"?

My two housemates have been going in circles about this. So I just wanna know what people here would think.