There is a study with the following abstract and reference:

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with a male-to-female prevalence of 4:1. However, the genetic mechanisms underlying this gender difference remain unclear. Mutation burden analysis, a TADA model, and co-expression and functional network analyses were performed on de novo mutations (DNMs) and corresponding candidate genes. We found that the prevalence of putative functional DNMs (loss-of-function and predicted deleterious missense mutations) in females was significantly higher than that in males, suggesting that a higher genetic load was required in females to reach the threshold for a diagnosis. We then prioritized 174 candidate genes, including 60 shared genes, 91 male-specific genes, and 23 female-specific genes. All of the three subclasses of candidate genes were significantly more frequently co-expressed in female brains than male brains, suggesting that compensation effects of the deficiency of ASD candidate genes may be more likely in females. Nevertheless, the three subclasses of candidate genes were co-expressed with each other, suggesting a convergent functional network of male and female-specific genes. Our analysis of different aspects of genetic components provides suggestive evidence supporting the female-protective effect in ASD. Moreover, further study is needed to integrate neuronal and hormonal data to elucidate the underlying gender difference in ASD.

Zhang, Y., Li, N., Li, C., Zhang, Z., Teng, H., Wang, Y., Zhao, T., Shi, L., Zhang, K., Xia, K., Li, J., & Sun, Z. (2020). Genetic evidence of gender difference in autism spectrum disorder supports the female-protective effect. Translational psychiatry, 10(1), 4. https://doi.org/10.1038/s41398-020-0699-8

Thank you for your comment. The study you cite provides interesting genetic insights but does not definitively explain the 4-1 male-to-female gender disparity for several reasons: 1) The higher mutational burden of de novo mutations found in females was only 0.13, which is too small to account for the gender disparity of 4-1. 2) Since females have two X chromosomes, one is randomly silenced in each cell, potentially rendering some detected mutations inactive, and therefore not a "burden." 3) Although de novo mutations can have a marked effect in causing autism, as the authors note, they account for less than half of cases. 4) While the study proposes that epigenetics—where DNA remains unchanged but environmental influences can dramatically affect gene expression—may play a role, the substantial evidence regarding environmental ASD risk factors suggests that the significance of genetics alone may be overstated. My hypothesis – that differences in brain growth and maturation and the timing of a potential epigenetic factor play a role – offers an alternative explanation for both autism’s gender disparity in prevalence and its gender-related differences in presentation.

It is not necessarily fact that more boys have autism than girls. It is the fact that girls mask (hide it) more than boys and therefore are less diagnosed. We are seeing a rise in diagnosis for girls due to social media such as tiktok but a big thing in Autism and neurodivergent community is self diagnosis which is still very much valid.