Gender-related distress will alleviate for around 80% of pre-teen children once they become teenagers.
Evidence from 10 available prospective follow-up studies  from childhood to adolescence indicates that childhood gender dysphoria will recede with puberty in ~80% of cases. A Dutch paper  notes that follow-up studies show the persistence rate of gender identity disorder to be about 15.8%, or 39 out of the 246 children who were reported on in the literature.
In one study  of 54 children referred to a clinic in childhood because of gender dysphoria and then later investigated by a follow-up study, only 21 (39%) still had gender dysphoria.
A different study  of Canadian boys with gender identity disorder showed that 87.8% desisted, with only 12.2% — fewer than 1 in 8 — persisting in their transgender identity.
An ~80% desistance is not universally found . Thorough investigations of the claims and counter-claims appear in two 2018 studies [6, 7].
 Kaltiala-Heino, R., Bergman, H., Työläjärvi, M., & Frisén, L. (2018). Gender dysphoria in adolescence: current perspectives. Adolescent health, medicine and therapeutics 9, 31–41. [Link]
 Steensma, T.D. & Cohen-Kettenis, P.T. (2011). Gender Transitioning before Puberty? Archives of Sexual Behavior 40 (4): 649-50. [Link]
 Wallien, M.S. & Cohen-Kettenis P.T. (2008) Psychosexual outcome of gender-dysphoric children. J Am Acad Child Adolesc Psychiatry 47 (12): 1413-23. [Link]
 Singh, D., Bradley, S.J. & Zucker, K.J. (2021). A Follow-Up Study of Boys With Gender Identity Disorder. Frontiers in Psychology 12. [Link]
 Temple Newhook, J., Pyne, J., Winters, K., Feder, S., Holmes, C., Tosh, J., Sinnott, M., Jamieson, A., & Picket, S. (2018). A critical commentary on follow-up studies and “desistance” theories about transgender and gender non-conforming children. International Journal of Transgenderism 19 (2). [Link]
 Steensma, T.D. & Cohen-Kettenis, P.T. (2018). A critical commentary on “A critical commentary on follow-up studies and “desistence” theories about transgender and gender non-conforming children”. International Journal of Transgenderism. [Link]
 Zucker, K. J. (2018). The myth of persistence. International Journal of Transgenderism 19 (2): 231-45. [Link]