A case heard by Taiwan's constitutional court today could make the country the first in Asia to approve same-sex marriage.

A panel of 14 justices will rule on a lawsuit that claims Taiwan's Civil Code, which defines marriage as between a man and a woman, is unconstitutional because it discriminates against gay couples. "Society recognizes gay people have the same needs," activist Chi Chia-wei told the court. "They are normal people wanting to build normal relations and the law should include them."

Chi says he is "cautiously optimistic" about the case, which comes as Taiwan’s parliament is considering a marriage equality bill. Should the court rule for the couple, though, it would make the measure moot and effectively legalize same-sex marriage.

Advocates have been heartened by the election last year of president Tsai Ing-wen, who has come out in support of marriage equality. Government representative Liao Yuan-hao argued legalizing gay unions would "not change the essence of marriage, but would solidify its values."

The issue has sparked great debate, though, with mass demonstrations on both sides in Tapei drawing thousands.

Justice minister Chiu Tai-san insists the civil code doesn't violate the constitution's guarantee of equality, because it doesn't specifically ban same-sex unions.

Calling for more consensus, Chiu argued that "abruptly changing [the law] will impact social order."