[See also this, the comments I made that I’m basing this on.]
In trans contexts, some people talk about the concept of an innate gender identity. I don’t think this exists, at least not in the sense it’s usually used.
Let’s come with one example. A common policy proposal is that you should respect people’s gender identity, e.g. by using the correct pronouns. This policy has important benefits and so I’m not here to argue against this policy, but it uses “gender identity” in a sense that’s generally not innate. For example, while many trans people end up developing secret suspicions that others may be “trans and repressing it”, few would say that in such cases they are obligated to start using different pronouns. And most people who advocate for this policy don’t think you should stop using the preferred pronouns if you conclude that the person in question transitioned for “the wrong reasons”.
Instead, this policy proposal uses a rather shallow notion of gender identity, usually something like “whatever the person states they are” or “whatever the person presents as”1. This shallowness is a feature rather than a bug, but it also means that the notion of “gender identity” used isn’t especially innate. In fact, most trans people change this identity in order to transition.
In addition to not being innate, it’s also not really what we usually mean by identity. Typically a social identity is defined by a strong expression of group allegiance. For instance, people who are politically active and have strong political opinions have a strong political identity; people who publically spend a lot of money and time on a specific subject can be said to have their interest in the subject as part of their identity; and people who strongly emphasize certain attitudes or personality traits that they have may be said to have these traits as part of their identity.
These sorts of identities probably serve many purposes. For instance, they let others know what they can expect of you, they let you precommit to certain roles, they let you signal your values or skills, and they let you define yourself more. It is probably nearly impossible to talk about identities without talking about their signalling value.
Gendered things can appear in these sorts of identities. Some people reject doing things that they consider too gender-nonconforming. Some men might feel embarrassed and emasculated if they had to do things that were too feminine. Some people make it clear that they reject unfair gender roles, and may change their presentation to signal this (e.g. butch women). Some people clearly express a preference for associating with women over men, or with men over women.
The thing about these sorts of social identities is that they’re not innate. You can’t be born with genes that specify a specific political party that you should endorse. A social identity is the story you tell about yourself, and this story is written by your interactions with the world. However, you can be born with innate propensities that affect how your story is likely to be expressed. If you are very open to experiences, you are less likely to end up with a conservative political identity. As such, simple tests for innateness will definitely hint to some innate elements. This applies to gender-related social identities too; how masculine or feminine you are is going to affect how you narrate your gender experiences.
Identities aren’t necessarily easy to change, though. If you’re a liberal activist, you’d probably find it difficult to become a conservative Christian. Part of this is the many commitments you’ve made. You’d have to replace a lot of your social circles, go back on many principles you’ve endorsed, and generally lose a lot of your current life. Part of it is that you probably became a liberal activist for a reason. You likely resonate a lot more with the liberal activist message than the conservative Christian one. Part of it would be embarrassment and psychological pain from such an abrupt shift. It would just look really weird.
But this sort of identity is often changed by transition. AGP trans women sometimes describe embarrassment and rejection of femininity pretransition; this is a masculine social gender identity. But afterwards, they typically embrace femininity very strongly, creating a feminine social gender identity. Thus, for AGPs, the social gender identity is generally an effect rather than a cause of their transition.
For HSTSs, it’s possibly more complicated. They tend to have a strongly developed GNC identity long before transition. Likely, this identity has a large effect on their transition. Perhaps among gender dysphoric kids, the “desisters” are those who wind down their GNC identity and “persisters” are those who keep building on it. This wouldn’t necessarily be about becoming less GNC, but could instead involve expressing the GNC in more socially-accepted ways. Perhaps something as simple as heterosexuality is enough to motivate winding down the GNC identity. But this is mostly speculation.
Regardless, even if one has a very masculine social identity, one can still feel a lot of pain about being male. (I’d know…) The desire to be of a certain sex is often called an affective gender identity, but I think it might be more intuitive to call it a gender aspiration. Regardless, I think when people talk about the notion of an innate gender identity, this is the concept they’re generally referring to. But this isn’t really an identity, even if it may be associated with one.
Is it innate? I think this depends on the person. An HSTS’s affective gender identity probably cannot be separated from their social gender identity and the trouble they experience when interacting with society. On the other hand, an AGP has a clear drive to become female (and an AAP a clear drive to become male) that is probably as innate as you’re going to get.
1. There are many variations of the policy of respecting people’s gender identity that can be done with different costs and benefits. I’m not here to advocate any specific one, as it’s outside the scope of this blog post.