How Can You Tell 100 Percent The Genetics Of A Person Who Is Multiracial?

The only way to do this accurately is to do a complete genotype of all of the family members and compare the results. The distinctions between races is much smaller than most people think. In fact, the distinction about race is quite artificial in a biological sense.

Ok to actually figure this out you need some real information rather than hypothetical theory but I will try and explain. Somewhere in the persons lineage there was a interracial couple, their off spring would be half and half for argument sake lets call it black and white. So this offspring is half black and half white. If it were to mate with another half black half white individual then the offspring would stay half black and half white in their heritage not necessarily their genes. However if the offspring were to mate with a pure bred (lets call it red) mate then their offspring would be 1/4 white 1/4 black and 1/2 red. If this offspring were then going to mate with a pure bred red then the new offspring will be 1/8 black 1/8 white and 3/4 red. The easiest way to do it is when you know the parents percentages you half all of them and then add like terms. So when a half black half white mates with someone who is the same background the offspring gets 1/4 white and 1/4 black from the dad and 1/4 white and 1/4 black from the mom. Then you need to add up the races that are the same and you get 1/2 white and 1/2 black. Hope this helps. Basically you need to know the racial percentages of the parents to figure it out. Oh and being cousins does not affect your race it may however affect other things such as intelligence or number of body parts lol.