The sex bias in autism diagnosis suggests the involvement of sex-specific endocrine mechanisms during prenatal development, but these hormones affect health throughout life. Therefore, the current study examined the association of autism and autistic traits with conditions and symptoms related to the sex-steroid system in adult women. In total, 1230 women (361 autistic), aged 15–77 years, reported on autistic traits and medical history. Medical diagnoses and symptoms were grouped by unsupervised factor analysis, and associations with autism diagnosis and autistic traits were explored. Higher rates of reproductive system diagnoses (odds ratio = 1.035, p = 0.024), prediabetes symptoms (odds ratio = 1.319, p = 0.001), irregular puberty onset (odds ratio = 1.458, p = 0.009), and menstrual length (odds ratio = 1.368, p = 0.034) and lower rates of metabolic and vascular conditions (odds ratio = 0.654, p = 0.013) were associated with diagnosis. Reproductive system diagnoses (β = 0.114, p = 0.000), prediabetes symptoms (β = 0.188, p = 0.000), menstrual length (β = 0.071, p = 0.014), irregular puberty onset (β = 0.149, p = 0.000), excessive menstruation symptoms (β = 0.097, p = 0.003), and hyperandrogenism symptoms (β = 0.062, p = 0.040) were also associated with autistic traits. Many of the conditions and symptoms found to be associated with autism or autistic traits are also related to conditions of steroid hormones and, specifically, the sex-steroid system. The study suggests an important role for steroids in autistic women, beyond prenatal development. Clinical implications are discussed. Lay abstract: Sex-steroids, such as testosterone, are thought to be one of the biological factors implicated in autism. This relies on the sex bias in the diagnosis of autism (boys are approximately four times more likely to be diagnosed than girls) and findings of associations with fetal testosterone levels in traits and abilities related to autism. The current study aimed to examine the association between medical conditions and physical symptoms, which tend to manifest in adulthood, and autism in females. Moreover, we examined their association with autistic traits throughout the spectrum. We focused on autistic women because there is little research focusing on the healthcare needs of autistic women, but those that exist suggest heightened vulnerability, and lower access to medical care. We find that conditions related to steroid hormones function are more frequent in autistic women and that they correlate with autistic traits. Specifically, we found that body mass index, reproductive system diagnoses, prediabetes symptoms, irregular puberty onset, and menstrual irregularities were significantly more frequent in autistic women and were significantly correlated with autistic traits in neurotypical women. The findings have important implications for raising awareness in autistic women of the possibility of medical conditions which might need medical attention. In addition, healthcare providers should consider these associations when performing healthcare maintenance checks and/or screening for autism.