3 ms·You can't as in it won't work. Not that eugenics as a whole can't work, but you can't back cross.by Vecr 3y agoYou can't as in it won't work. Not that eugenics as a whole can't work, but you can't back cross.dekhn 3y agoWhy can you back-cross in mice but not humans? That doesn't sound right.Vecr 3y agoI'd have to check the source. What traits are they looking for in the mice?