STUDY QUESTION: What methods are used by sexual and gender minority (SGM) parents to build their families? SUMMARY ANSWER: SGM parents used diverse methods to build their families, which varied both by gender identity and age. WHAT IS KNOWN ALREADY: Despite experiencing significant barriers to becoming parents, 63% of SGM adults aged 18-35 years old are considering having children or expanding their family. Data on US same-sex couples demonstrate that although most same-sex parents (68%) are genetically related to their children, they are more likely to adopt, foster, and be step-parents compared with different-sex couples. STUDY DESIGN, SIZE, DURATION: Cross-sectional analysis of 2018-2020 data from The PRIDE Study, a community-engaged longitudinal cohort study of SGM adults living in the USA. This analysis included 2122 SGM parents with 4712 children (median of 2 children per parent). PARTICIPANTS/MATERIALS, SETTING, METHODS: Primary exposures were SGM subgroups (cisgender sexual minority men, cisgender sexual minority women, gender diverse people assigned female at birth [AFAB], gender diverse people assigned male at birth [AMAB], transgender men, and transgender women) and age cohorts (18-39, 40-54, and 55 and older). The primary outcome was method of family building, grouped into three overarching categories defined as (1) pregnancy from sexual activity, (2) pregnancy without sexual activity (e.g. use of donor gametes, surrogacy), and (3) a method other than pregnancy (e.g. adoption, fostering, step-parenting). We used logistic regression models to evaluate differences in methods of family building used by SGM subgroup and age groups. MAIN RESULTS AND THE ROLE OF CHANCE: Overall, 56% of SGM adults became parents through pregnancy from sexual activity, 14% became parents through pregnancy without sexual activity, and 28% became parents from a method other than pregnancy. Transgender women, gender diverse parents, and cisgender men had a higher odds of using pregnancy through sexual activity to become parents and were less likely to become parents using pregnancy without sexual activity compared with cisgender women. Conversely, transgender men were less likely to use pregnancy through sexual activity (aOR 0.57, 95% CI 0.44, 0.73) and over twice as likely to use methods other than pregnancy (aOR 2.39, 95% CI 1.86, 3.06) compared to cisgender women. Parents aged 18-39 and 40-54 years old were twice as likely to use pregnancy without sexual activity compared with parents aged 55+ years old (Age 18-39: aOR 2.16, 95% CI: 1.55, 2.99; Age 40-54: aOR 1.92, 95% CI: 1.39, 2.66). LIMITATIONS, REASON FOR CAUTION: Our convenience sample was predominantly White. We are unable to infer information about the preferred methods or attempted but unsuccessful methods of family building. WIDER IMPLICATIONS OF THE FINDINGS: The number of SGM parents is likely to grow, given that younger generations are more likely to identify as SGM, desire children, and have access to medically assisted reproduction. Clinicians must be aware of the diversity of methods SGM parents used to become parents and the financial, legal, and institutional barriers that SGM people navigate when building their families. STUDY FUNDING/COMPETING INTEREST(S): Funding for this work was provided by the Stanford Maternal and Child Health Research Institute Seed Grant program to J.O.M. and S.L. and the Stanford University School of Medicine Department of Obstetrics and Gynecology. Research reported in this article was partially funded through a Patient-Centered Outcomes Research Institute (PCORI) Award [award number PPRN-1501-26848] to M.R.L. The statements in this article are solely the responsibility of the authors and do not necessarily represent the views of PCORI, its Board of Governors or Methodology Committee, or the National Institutes of Health. J.O.M. was partially supported by the National Institute of Diabetes, Digestive, and Kidney Disorders [grant number K12DK111028]. A.F. was partially supported by the National Institute on Drug Abuse [grant number K23DA039800]. The funding sponsors had no role in study design; the data collection, analysis, and interpretation of data; the writing of the report; the decision to submit the article for publication; or the preparation of the manuscript. Dr Obedin-Maliver has received grants and consultation fees from Ibis Reproductive Health, Hims and Hers Health Inc., Folx Health Inc., Sage Therapeutics and Upstream Inc. on topics unrelated to this work. Dr Lunn received consultation fees from Hims and Hers Health Inc., Folx Health Inc., Otsuka Pharmaceutical Development and Commercialization, Inc., and the American Dental Association on topics unrelated to this work. All other authors have no conflicts of interest to report. TRIAL REGISTRATION NUMBER: None.