A common misconception in regards to the augmentation procedure. It doesn't sterilize them, it simple has a chance to reduce their sex drive. As for Randall-037, I give you 343i's biography of him: [quote]He participated in 59 large-scale conflicts and military operations against the Covenant from 2525-2532; conversely, he had very few engagements with insurgent humans prior to the opening of the Covenant War, though he was involved in a failed effort to retrieve fellow Spartan Soren-066, who had plotted to defect to the side of the rebels after complications during his augmentation process. Soren-066 was believed to have perished during his escape from Reach, providing a huge blow to Randall-037’s confidence, though he overcame the hurdle thanks to the encouragement of Chief Petty Officer Franklin Mendez. In 2532, during the Battle of Vodin, Randall-037 was thought lost during an orbital space engagement with the Covenant. ONI deemed him an ‘unrecoverable asset,’ officially being listed as MIA. In reality, Randall had fallen from the planet’s skyhooks into Vodin’s atmosphere and plunged to the surface, surviving impact by landing in one of the colony’s oceans. He was rescued days later by locals who had also survived the Covenant assault. Though severely damaged in the attack, the colony was still habitable and Randall integrated with the local survivors as he recovered from his injuries. With all outbound communication and transport equipment destroyed in the Covenant attack, Randall-037 lived with the survivors of Vodin for a full decade, even marrying one of the colonists, before they finally regained contact with the UNSC. By that time, however, his ties to the people of Vodin and his wife were too strong for him to return to service, and so Randall-037 – now going by the name Aiken – decided instead to keep a low profile and remain on Vodin. In 2545, Aiken and his wife had a daughter named Natalie. Tragically, Aiken’s wife died during childbirth. In 2546, ONI finally located him and made plans to reintegrate him into service, as they viewed him as a huge investment of the SPARTAN-II program. When Aiken refused, ONI deemed him compromised and no longer viable as a Spartan and so made plans to “decommission” him. Aiken forcefully (and successfully) refused this effort, but eventually negotiated a deal where ONI reversed many of his augmentations (in what would be an excruciating process) in return for his release from service to the UNSC. After his dealings with ONI were complete, Aiken and his daughter left Vodin and headed to the remote colony of Sedra where he enrolled as part of the Colonial Guard. Thanks in large part to his extensive training and history, by 2556 he advanced to leader of the local wing of the Guard as a Colonel.[/quote]