This is a very good representation of "genes" actually. Most of the replies that you have recieved have focused exclusivley on human genetics requiring two parents and sex. Mimicing humans makes little sense but to boost our own egos really. Different systems of genetics occur in large multicelular organism due to the difficulty in promoting diversity and evolution due to much longer generation times. For a robot that can demonstrate extreemly fast reproduction and generation times having two parental sources really isn't a necessity.
What you describe is very simular to genetic change in microbes, and I think it would be good to stick to it.
Heck you could even put some code into them that would occasionally allow them to transfer "genes" to another robot and see what effect that has and if this code itself would be promotted.
Good Job.