the purpose of sex in biological systems is to speed up the rate of genetic change and introduce mutation at a faster rate, there is no reason why Genetic Algorithms couldn't fill this void, OR have two programs collaborate on a set of goals, (i.e. two programs acts as checks and balances for the design of some other program that solves a goal that both parent program understand; (i.e understand not reason about), at that point though, that wouldn't be 'sex', that would just be a collaboration of two programs. Example, two ruby programs get together and write a C program, that in turn could collaborate with the two ruby programs to design and create a 4th program; and perhaps in a different language.)