In interpreting the state equal protection guarantee, Illinois courts follow federal precedents interpreting the Equal Protection Clause. But there is no Supreme Court decision subjecting classifications based on sexual orientation to the standards that apply to classifications based on race (strict scrutiny) or gender (intermediate scrutiny). In Romer v. Evans (1996), the Supreme Court struck down Colorado’s Amendment 2, which barred special legislation protecting gays and lesbians, under the rational basis standard of review. But the narrow and focused prohibition of same-sex marriage cannot be equated with the breadth and scope of Amendment 2. And every federal court of appeals to have considered the issue has concluded that classifications based on one’s sexual orientation are subject only to the “rational basis” standard of review.
The reservation of marriage to opposite-sex couples easily passes that standard. Extending marriage to same-sex couples would not promote either of the two primary purposes for which society recognizes the institution of marriage””providing a stable environment for children procreated by heterosexual sexual activity and providing the benefits of dual-gender parenting for the children so procreated.