I'm fairly certain that Spartan II's cannot reproduce, for a few reasons, but I'll put the main one. Spartan II augmentation altered molecules. If you were to do that it would HAVE to be genetic, otherwise your body would not recreate the augmentations during cell division, and the augmentations would only last until the majority of the augmented cells had died of natural causes. seeing as the Spartan II's were children when abducted, they would have had to grow, which means that cells had to divide, meaning the traits were genetic. During reproduction, you give half of the child's genetic structure, and Spartan II's would have abnormal genetics, resulting in three possible outcomes. 1. The child is incompatible with the mother, and is miscarried early on, if at all conceived. 2. There is a child, but the genetic alterations did not mesh properly with the genes of the mate, resulting in a crippled child similar to those who were "washouts" of the original program. 3. There is a child, and it has the same genetic capabilities as the Spartan II parent, however due to not having a natural reinforced skeleton or post gene therapy altered developmental glands, the child ends up with either elephantitis or some other issue where the bones cannot support muscle mass or other results of the gene tampering. In case 2 and 3, the child would also most likely be sterile.