Agree, it's a totally plastic (i.e. artifitial) character, nothing she did felt real, even the sex was as un-sexy as it gets and the 'shocking' scenes such as the dog poo stoppage are completely unremarkable.
We do find the sex of the kid, he is a boy, it is hinted at first when she is thinking about taking estrogen gel, and she mentions that perhaps 'they' will need their own soon (I mean, talk about a totally superfitial understanding of the subject, who in their right mind would medicallize a feminine boy. Oh, yeah, lots of people, but still doesn't make it right and hopefully very soon it wil be seen everywhere for what it is).
And then, when she and her husband (the most unrealistic/superfitial man portrait in the world) are role-playing when making up after towards the end, he says it's her son.
Interestingly, I listened (for as long as I could) a podcast with her. It is semi-autobiagraphical, she and her husband have a relationship like tha one developed in the book, and she has a boy whom she describes as fem non-binary.
Also, even more interestingly from an ideological point of view, in the acknolegements one of the people she thanks is Ayden Olsen-Kennedy, who is the trans husband of Dr Johanna Olsen-Kennedy, director of the Centre for Transgender Health and Development Children’s Hospital, Los Angeles and recipient of the $5.7 million grant from the NIH to study the effects of early medical interventions for adolescents with gender dysphoria, which she has never published, allegedly because the results didn't support her work, and who is currently being sued by a detransitioner whom she referred to a double mastectomy at the age of 14.
Sorry to ofload all of this here, I am discussing this book with a book club to which I am quite new and am of two minds whether to open my big mouth at it. So thank you MN for letting me write this!