People with sexual minority (SM) identities are less likely to aspire to be parents than their heterosexual counterparts. This differential may be due to concerns by SM people about their child(ren) encountering prejudice or discrimination. The objective of this study is to empirically examine whether SM respondents' rationales for not having children are due to concerns that their child(ren) will be treated unfairly. We draw on the National Couples' Health and Time Study (NCHAT), a nationally representative study of partnered adults conducted between September 2020 and April 2021. The NCHAT includes oversamples of sexual and gender minority people. We include SM respondents under 50 and are not currently intending to have a child (n=1,079). About half reported that they were avoiding having a child due to concerns about how their child(ren) would be treated because of their own sexual or gender identity. SM people in same-gender couples had significantly higher odds of being concerned about their potential child's treatment than those in different-gender couples, and these results persisted with the inclusion of sociodemographic indicators. This study is one of the first to quantitatively examine mistreatment as a potential barrier to family building among sexual and gender diverse individuals.