Swiss citizens voted on Sunday to amend the Swiss Civil Code to legalize same-sex couples’ right to marry and to adopt children. Voters accepted the proposal in a 64 to 36 percent vote.

The Swiss Federal Council and Parliament called for a referendum and endorsed same-sex marriage. They explained that although same-sex Swiss couples could enter into registered partnerships, and about 700 couples did so every year, such couples could not marry. The council and Parliament proposed eliminating family inequality by opening marriage to all couples, granting same-sex couples the right to adopt children, and allowing all couples access to legally regulated semen.

Opponents challenged the proposed amendment, arguing that granting same-sex couples the right to marry would violate the Swiss constitution. They reasoned that their constitution grants opposite-sex couples the right to marry because opposite-sex couples can “pass on life.” Opponents further contended that marriage should be limited to opposite-sex couples so as to “protect the cornerstone of society and the state.” In support of this contention, they said that children’s best interests should be protected in a household with “role models from both genders.”

The Swiss Federal Council and Parliament countered, observing that children were already growing up in households with two mothers or two fathers. Hence, they argued that allowing same-sex couples to marry and legitimately raise children in attentive and caring homes served children’s best interest. The council and Parliament also noted that this right would not change marriage between a woman and man, and it would limit the government’s ability to interfere with citizen’s private lives.

After Swiss voters accepted the amendment in a two-thirds majority, Director of Amnesty Switzerland Alexandra Karle expressed support for the “historic vote,” which will make Switzerland the 29th country to legally permit same-sex marriage. Karle said, “Marriage—and with it the right to found a family—will finally be open to all couples in Switzerland. This is an important step towards equality, which was long overdue.”