Every time she pops out a kid he goes to jail.
I mean fuck, I would just not tell anybody we were bother and sister. It's only illegal if everybody finds out.
Those two look seriously retarded though, so maybe for the sake of mankind we should stop them from breeding.
The risk of genetic problems through incest isn't actually much increased in one generation. Genetic diversity under normal circumstances is high enough even between brother and sister pairings. Certainly there is no technical problems in doing your cousin at least.
Who is harmed by this act? Shouldn't be criminal.
If you practiced line breeding that would be another thing.