London - Northern Ireland's regional health minister resigned on Monday after saying that children of same-sex couples were more at risk of being abused or neglected.
Jim Wells was also placed under investigation by police over alleged comments made to a lesbian woman while out campaigning for next week's general election.
Wells said in a statement that he and his family had been attacked on social media "in a deeply personal, nasty and, in some cases, threatening way".
The issue of same-sex marriage is hugely controversial in Northern Ireland, the only part of the United Kingdom that does not allow it and which also bans abortion.
Northern Ireland's regional assembly was debating same-sex marriage on Monday but attempts to legalise it have been rejected by local politicians in the past.
The neighbouring Republic of Ireland is set to vote to allow same-sex marriage in a referendum next month.
Wells, a devout Christian from the Democratic Unionist Party, apologised last week after saying at a campaign event that "facts show you certainly don't bring a child up in a homosexual relationship".
He is also being investigated following a complaint by the daughter of a lesbian woman who said that her mother had been upset following an exchange with Wells when he came campaigning to their house.