Sweden's parliament approved Wednesday same-sex marriage legislation, which will take effect on May 1.

Previously, two people of the same sex could register their partnership. With the new "sex-neutral" law, sex will no longer matter when two people want to get married. Couples who already had a registered partnership can now either stay in that union or transform it into a marriage if they wish, the Parliament web site said.

"Unfortunately this is not an April Fool's Day joke, this is reality," Yvonne Andersson, member of the Swedish parliament for the Christian Democrats, wrote on the party's Web site following the vote. The Christian Democrats was the only party opposed to the new law.

The party had instead proposed a law that would remove the word "marriage" from Swedish law and replace it with a legally binding union between two persons, thus separating it from the Christian ceremony that the church conducts.

"This was the last area where same sex couples were treated differently. Wednesday's vote means a very important change in Swedish law", secretary general of the Swedish Association for Sexuality Education, Asa Regner, told CNN.