AFAICT It seems to be answered in terms of the sex of their partners post-transition, i.e. a hetero MTF would prefer sexually-male partners.

The fact that the 59% stat for history of rape is symmetrical for MTF and FTM really bugs me, though. It seems to imply weird causal arrows pointing in completely opposite directions depending on whether you were originally male or female, based on my prior knowledge.

Which seems very scary, because it could also imply that MTFs are a dozen decibels more likely to be targets of rape than average females. Now I wonder if that has been taken into account when looking at the mental health stats.