IN CONSERVATIVE Asia, Taiwan has given the warmest embrace to gays and lesbians. Before he became president in 2008, Ma Ying-jeou was mayor of Taipei, the capital. He boasts that he made it the most gay-friendly city in Asia, even devoting a portion of the municipal budget to homosexual causes. Taiwan routinely holds Asia’s largest gay-pride march; the latest one, in October, attracted over 60,000 people. Recently a bill allowing same-sex marriage and married gay couples to adopt children passed its first reading in the island’s legislature.

But it has put the country’s liberal tendencies to the test. A survey conducted by TVBS, a broadcaster, suggests that 40% of Taiwanese are in favour of the same-sex marriage bill and 45% against. On November 30th over 150,000 Taiwanese rallied to show their opposition. The crowds waved pink and blue placards depicting a nuclear family. They voiced concerns about the decline of traditional family structures. Children could become confused about their gender, marchers claimed. It would only reinforce the long-run decline in the fertility rate.

Supporters of gay marriage said the large turnout was thanks to conservative Christians, a small but outspoken minority. But rally organisers said Christians formed only a part. Several lawmakers from Mr Ma’s ruling party, the Kuomintang, attended.

It is unclear whether the bill will now pass, but Victoria Hsu, head of the Taiwan Alliance to Promote Civil Partnership Rights, which pushed for it, is optimistic. The mass turnout against it will galvanise those who are for, a group that includes many students and academics.

Opponents are demanding a referendum, should the bill eventually pass. This might worry China. It claims Taiwan as its own and frowns on referendums, which smack of self-determination, even more than it frowns on gays. Mr Ma, famous for his caution, will be torn over whether to please the pros or the antis.