The bill awaits approval from the two houses of congress to pass, which would also permit LGBT couples to adopt children.
Currently, only marriage between a man and a woman is recognised in Chile. Two years ago, Chile legalised civil unions of same-sex couples. The bill was signed at La Moneda Palace, the presidential palace. LGBT activists attended the signing ceremony; at least 200 attendees were expected.
Chile is a largely Roman Catholic country, and the Roman Catholic Church has been against the idea of same-sex unions. During the signing ceremony, Bachelet said, "it is not ethical nor fair to put artificial limits on love". She tweeted, "For love there are no conditions. For moving forward towards an inclusive Chile, today I signed bill of #EqualMarriage ((es)) "
Under Bachelet's presidency, Chile saw changes in the abortion laws last week. Abortions are now allowed for cases like pregnancy from rape, or conditions endangering the mother's life or where the foetus cannot survive. Chile saw a total ban on abortion in 1989 under General Pinochet. Bachelet's term is to end in March. Former president and candidate in November's Chilean presidential election Sebastián Piñera is against the legalisation of same-sex marriage, and said: "There should not be discrimination, but at the same time the essence of an institution such as marriage should be respected, which has always been about conserving the human race".
Sex among partners of the same gender has been legal in Chile since 1999. Argentina, Brazil and Uruguay are among South American countries where same-sex couples are allowed to marry.
'In July the German Bundestag also voted for same-sex marriage.'Civil Rights Progress