Many scholars have called for the acknowledgement and treatment of children's rights as constitutionally protected and enforceable, and Supreme Court precedent establishes that the government may not punish children for matters beyond children's control. Same-sex marriage bans and non-recognition laws, which are collectively referred to as marriage bans, impose prohibited punishment on children for being born into, or parented by, same-sex families. States argue that marriage is the optimal familial environment for children, yet marriage bans categorically exclude an entire class of children -- children in same-sex families -- from the legal, economic, and social benefits of marriage. In response to this reality, rather than States' rhetorical characterization of marriage bans as child welfare measures, this amicus brief filed with the Supreme Court in Obergefell v. Hodges, and relied on by the Court in its majority opinion, highlights the adverse impact of marriage bans on children's best interests.