Geoffrey R. Stone, a distinguished law professor at the University of Chicago law school and chair of the ACS Board of Directors, says the Supreme Court has "concluded that the proper application of the Clause requires the use of heightened scrutiny to test the constitutionality of laws that discriminate against African-Americans or that discriminate against other groups in society that are similar to African Americans for purposes of the Equal Protection Clause."
The high court, Stone continues, looks at several factors to determine whether the Equal Protection Clause protects a group from discriminatory laws. The high court asks whether the group has been "subjected to a history of discrimination," whether it can "effectively protect itself in the political process," whether the "group is objectively different in some meaningful way that would logically justify treating its members differently than others," and "whether the group's status is immutable," Stone writes.
Using that criteria, Stone says the high court has found that "laws that discriminate against ethnic minorities and women are sufficiently similar to laws that discriminate against African Americans to justify testing them by heightened scrutiny."
For gay men and lesbians the only criteria that might be questioned is whether the group's status is immutable. Stone notes that there is a "general consensus today that one's sexual orientation is not a matter of choice."
Although there are those who dispute this proposition, the great weight of the evidence cuts the other way. If you are a heterosexual, imagine if you suddenly had to lead your life as a homosexual. All of your instincts would cut strongly in the opposite direction. You might be able to force yourself to engage in sex with people of the same sex, but it would seem wholly unnatural and, more importantly, you would continue (secretly) to be attracted to persons of the opposite sex, even if you could no longer legally act on those attractions. This is pretty much what sexual orientation means, and in its deepest sense the orientation seems to be beyond one's own control. One can (perhaps) change one's conduct, but not one's orientation.