You see where I'm going with this I'm sure.
Gynephilic transsexuals have been accused of being sexually motivated in their decisions to transition and the theory postulated was that they were attracted to their own image and hence had an alternate sexual orientation. But then why were they also marrying women and helping to conceive children?
Regardless of orientation, pre-transition male to female transsexuals should generate comparable levels of testosterone with the key difference being that androphilic transsexuals don't find women sexually attractive. Their gender dysphoria causes them to want to be and live as women without the contradiction that gynephilics experience. Hence the sexual equation drops out for them.
In the case of female to male transsexuals any sexual component to their dysphoria would be less evident since women tend to be less driven by sex due to the lower levels of testosterone they produce. This is why women generally tend to look more for a more holistic type of bond with their partner and find attachment on numerous levels which include but are not limited to sexual attraction.
Most gynephilic transsexuals of my generation or previous became confused and dismayed by the presence of any sexual overtones that puberty brought and needed to sort out the conflict inherent in being attracted to women while wanting to be one. Once this calms with increasing age, they found the dysphoria they experienced as a child remained intact. After so many years in hiding they would typically then face it head on because they cared less about what people thought and because their lives were less complicated by then with not needing to worry about grown children and financial burdens.
That decision didn't always necessarily involve a full transition but to introduce some means of coping and finally come out to others.
What is happening now with younger gynephilics is that they are looking past the sexual overtones and understanding themselves much sooner in this more open and knowledge-based environment. The result has been transitions at younger ages for those who require them.
It is worth noting that when estrogen is introduced to the gender dysphoric male the libido is reduced and their dysphoria is quelled with no regret as to their changing bodies which suggests that sexual motives were not a primary driver. Were you to do that to a non-dysphoric they would become extremely despondent to say the least.