In A Blagger's History of Torei, it's speculated that the AIs engineered the humans on Torei to produce 9 women for every man. This was likely part of an initial population surge, but the humans gained independence before this could be changed back.
The fact that the gender ratio has not changed since, despite the advanced biotech available to the Ministry of Improvements, hints that either the Ministry itself, the men in charge or the AIs in the shadows are still interested in maintaining the skewed gender ratio. It is next to impossible for a woman (and even a man!) to specifically request a male birth from the MoI, even though it is certainly within the ministry's power. Gender selective pregnacy technology is the only biotechnological advance that Toreans import - almost always illegally and at great risk.