History, however, shows that same-sex marriage was both legal and accepted in First Century Rome. Lifesite News re-published this article from Catholic World Report to demonstrate ancient Rome's acceptance of homosexuality. The author concludes:
We can see, then, that Christians face nothing new in regard to the push for gay marriage. In fact, it is something quite old, and represents a return to the pagan views of sexuality that dominated the Roman Empire into which Christianity was born.
Other sources confirm that Paul's culture (remember, he had Roman citizenship) accepted both homosexuality and same-sex marriage. Consider the following excerpts from Random History's article, Same-Sex Unions Throughout Time:
Classical antiquity in the Western world is frequently cited for examples of same-sex love and relationships, though separate concepts of homosexuality and heterosexuality did not exist in the same way as today. Plato’s Symposium, for example, describes instances of homosexual attraction and same-sex relationships in ancient Greece without condemnation. Some point to examples of same-sex interaction in Greek artwork as further evidence of its equal status within the society. Individual, higher status, however, was of critical importance to free expression of love.
Roman social customs are relatively well known, and same-sex unions existed as high in society as among Roman emperors. Roman statesman Cicero also documented legal rights of an individual within a same-sex marriage. Female same-sex unions seemed to have been less common, but only because women enjoyed less freedom in their economic and social endeavors (Eskridge).
Because Paul was highly educated and cosmopolitan, surely he understood the place of homosexuality in Greek and Roman society! Certainly, homosexual prostitution had connections to idolatry and pagan worship, but loving relationships existed just as much then as they do now. To claim that Paul knew nothing of loving, committed gay relationships suggests an ignorance of history, as well as an eagerness to circumvent the Bible's authority. Therefore, it is not a convincing argument.