New Zealand’s Catholic bishops described as “bizarre” parliament’s vote that discards the understanding of traditional marriage when it approved a same-sex marriage law.

The bishops said the April 17 action was taken despite widespread opposition.

“We find it bizarre that what has been discarded is an understanding of marriage that has its origins in human nature and common to every culture, and that almost all references to husband and wife will be removed from legislation referencing marriage,” said Archbishop John Dew of Wellington, president of the New Zealand Catholic Bishops’ Conference.

Dew said marriage is based on sexual difference and the traditional definition of marriage reflects that understanding.

New Zealand became the 13th nation to recognize same-sex marriage.