The East Orthodox believe that, yes, homosexuality is a sin, even in mere thought, but no greater than any other sin. Even Saint Paul puts it in the list along with adultery, theft, murder et al. The notorious passage in Romans chapter 1 refers to a special type: those who justify homosexuality as not a sin.

Even in the Greco-Roman classical period, when homosexuality was considered acceptable, it was not something to be flauted. For example, the papyri discovered at Oxyrhinchus include marriage proposals where the man is not allowed to bring in either another wife or boy into the household.