Lawrence v. Texas & Defamation Law
The Leonard Link Blog has this post that begins:
Under the common law, wrongly calling somebody gay could get you sued for defamation and you would almost automatically incur damages, even if the plaintiff could not prove that they had suffered any tangible loss as a result. In cases of defamation “per se,” courts would presume an injury that had to be compensated. The underlying rationale for this was that an “imputation of homosexuality” was tantamount to a charge of sexual criminality. Of course, prior to Illinois’s adoption of the Model Penal Code reforms in 1961, gay sex (and all anal or oral sex, actually) was unlawful in every U.S. jurisdiction.
The post goes on to argue that Lawrence v. Texas has changed the rule and the culture.