Ray Blanchard and J. Michael Bailey explain here that all males who who develop "gender dysphoria" in adolescence or adulthood do so because of autogynephilia (AGP);

Autogynephilia is a male’s sexual arousal by the fantasy of being a woman. That is, autogynephilic males are turned on by thinking about themselves as women, or behaving like women. The typical heterosexual adolescent boy has sexual fantasies about attractive girls or women. The autogynephilic adolescent boy’s may also have such fantasies, but in addition he fantasizes that he is an attractive, sexy woman. The most common behavior associated with autogynephilia during adolescence is fetishistic cross dressing. In this behavior, the adolescent male wears female clothing (typically, lingerie) in private, looks at himself in the mirror, and masturbates. Some autogynephilic males are not only sexually aroused by cross dressing, but also by the idea of having female body parts. These body-related fantasies are especially likely to be associated with gender dysphoria.

Blanchard’s research identified two distinct subtypes of gender dysphoria among adult male gender patients. One type, which he called “homosexual gender dysphoria” is identical to childhood onset male gender dysphoria. Males with this condition are homosexual, in the sense that they are attracted to other biological males. Blanchard provided persuasive evidence that the other male gender patients were autogynephilic.

We currently favor the theory that there are only two well established kinds of gender dysphoria among males, because no convincing evidence for any other types has been offered. This could change­–we are committed to a scientific open-mindedness. In particular, it is possible that some cases of adolescent-onset gender dysphoria among males are essentially the same as Rapid-onset Gender Dysphoria that occurs among natal females. This will require more research to establish, however.

Autogynephilia is a probably rare, although it is difficult to know for certain. Among males who seek gender transition, however, it is common. In fact, in Western countries in recent years, including the United States, autogynephilia has accounted for at least 75% of cases of male-to-female transsexualism.

It is important to distinguish between autogynephilia and autogynephilic gender dysphoria. Autogynephilia is basically a sexual orientation, and once present does not go away, although its intensity may wax and wane. Autogynephilic gender dysphoria sometimes follows autogynephilia, and is the strong wish to transition from male to female. A male must have autogynephilia to have autogynephilic gender dysphoria, but just because he is autogynephilic doesn’t mean he will be gender dysphoric. Many autogynephilic males live their lives contented to remain male. Furthermore, sometimes autogynephilic gender dysphoria remits so that a male who wanted to change sex no longer does so.

In general, adolescent boys are unlikely to divulge their sexual fantasies to their parents [or other adults such as their therapists, doctors, teachers or clergy]. This is likely especially true of boys with autogynephilia. Furthermore, many boys who engage in cross dressing feel ashamed for doing so. The fact that autogynephilic fantasies and behaviors are largely private is one reason why autogynephilic gender dysphoria usually seems to emerge from nowhere. Another reason is that autogynephilic males are not naturally very feminine. An adolescent boy with autogynephilia does not give off obvious signals of gender nonconformity or gender dysphoria.

It is likely that most autogynephilic males do not pursue gender reassignment, but this is difficult to know. (We would need to conduct a representative survey of all persons born male, asking about both autogynephilia and gender transition. This has not been done and won’t be done anytime soon.) Many males with autogynephilia are content to cross dress occasionally. Some get married to women and many also have children. Family formation is no guarantee against later transition, although that may slow it up somewhat. In past decades, when autogynephilic males have transitioned, they have most often done so during the ages 30-50, after having married women and fathered children. It is possible that autogynephilic males have recently been attempting transition at younger ages, including adolescence.

Given how important autogynephilia is for understanding gender dysphoria, it may surprise you that you had never heard of it. Autogynephilia remains a largely hidden idea because most people–including journalists, families, and many males with autogynephilia–strongly prefer the standard, though false, narrative: “Transsexualism is about having the mind of one sex in the body of the other sex.” Many people find this narrative both easier to understand and less disturbing than the idea that some males want a sex change because they find that idea strongly erotic.

Although many autogynephilic males find discovery of the idea of autogynephilia to be a positive revelation–autogynephilia has been as puzzling to them as it is to you–some others are enraged at the idea. There are two main reasons why some autogynephilic males are in denial. First, they correctly believe that many people find a sexual explanation of gender dysphoria unappealing–discomfort with sexuality is rampant. Second, they find this explanation of their own feelings less satisfying than the standard “woman trapped in man’s body” explanation. This is because autogynephilia is a male trait, and autogynephilia is about wanting to be female.

Males with autogynephilia can have a variety of autogynephilic fantasies and interests, from cross dressing to fantasizing about having female bodies to enjoying (for erotic reasons) stereotypical female activities such as knitting to fantasizing about being pregnant or menstruating. One study found that autogynephilic males who fantasize about having female genitalia also tended to be those with the greatest gender dysphoria.

Autogynephilic males sometimes identify as heterosexual (i.e., attracted exclusively to women); sometimes as bisexual (attracted to both men and women), and sometimes as asexual (i.e., attracted to no individuals). Blanchard’s work has shown that autogynephilia can be thought of as a type of male heterosexuality, one that is inwardly directed.

Autogynephilia often coexists with outward-directed heterosexuality, and so autogynephilic males usually say they are also attracted to women. Some autogynephilic males enjoy the idea that they are attractive, as women, to other men. They may have sexual fantasies about having sex with men (in the female role); some may even act on these fantasies. This accounts for the bisexual identification among some autogynephilic males.

In some others, the intensity of the autogynephilia–which is attraction to an imagined “inner woman”–is so great that there are no erotic feelings left for other people. This accounts for asexual identification. (Asexual autogynephilic males have plenty of sexual fantasies, but these fantasies tend not to involve other people.)

When autogynephilic males receive female hormones as part of their gender transition, they typically experience a noticeable decrease in their sex drive. Some have reported that this has diminished their desire for gender transition as well. Others, however, have reported no change in their desire for transition. (In any case, hormonal therapy is a medical intervention with serious potential side effects, and we do not recommend it as a way to treat gender dysphoria, except in cases in which after very careful consideration, gender transition is pursued.)

Autogynephilia is a paraphilia,** meaning an unusual sexual interest nearly exclusively found in males.

https://4thwavenow.com/2017/12/07/gender-dysphoria-is-not-one-thing/

** Paraphilia (previously known as sexual perversion and sexual deviation) is the experience of intense sexual arousal to atypical objects, situations, fantasies, behaviors, or individuals: Wikipedia

Paraphilias are known to occur mostly - indeed, exclusively - in males, though this might be merely because males and their sexuality have been studied much more than females and female seuxality.

Paraphilias in men have also been found to occur in clusters - a man with one paraphilia will typically have others. But this might be a reflection of the population of paraphiliac men who have been studied the most, who have either been men who have been incarcerated (many of them for sex crimes) or ended up in the care of psychotherapists or medical doctors for their sexual issues, including transvestism and desire to "transition."

A problem with paraphilias is that many of the men with atypical sexual desires, urges and fantasies of feel compelled to act out their sexual desires and fantasies in ways that involve other people, including others who do not wish and have not consented to playing a part in these men's sex lives. Violating the boundaries of others and being abusive to them in a wide variety of ways tends to go hand in hand with paraphilias - and many of with paraphilias need an audience for their deviant behaviors and get off on making other people uncomfortable. Hence the demand that others recognize and "validate" that men with AGP are women. An example is someone like Jonathan Yaniv, aka Jessica Yaniv, now "Jessica Simpson."

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3769077/

https://labs.la.utexas.edu/mestonlab/sexual-paraphilias/