@Bad Thoughts, my best guess would be that, barring genie magic intervention saying otherwise, the child would essentially be a clone of whichever version of him they most closely matched chromosomally? (with all the chances of minor mutations, including the possibility of chromosomes being neither XX or XY, inherent in the reproduction process)
I only just now noticed that although events are so far proceeding almost exactly like in the first time through, SHE'S NOT BRUNETTE HERE, like she was the first time through. It's not a perfect time loop! Genie couldn't quite remember what the last thing was and guessed "long hair", but the actual request was "long dark hair". Are they gonna break time?