SNP MP Dr Lisa Cameron says an elderly relative has received a death threat after she voted against a Bill to criminalise prayer vigils outside abortion clinics.
The Bill passed by 213 votes to 47 last month but as a Ten Minute Rule Motion it is unlikely to become law.
Dr Cameron was one of the few MPs to vote against the measure and the only member of the SNP to do so.
After the vote, she discovered a message on her Facebook page from a person who called the MP a "fat slag" and said they planned to kill her relative.
The message has been reported to the police.
"I am concerned by the actions of those who have whipped up hatred and toxic aggression online in recent weeks following from my conscience votes on abortion and particularly distressed to have once again received a death threat towards my family," she said.
"Unfortunately, it is becoming more difficult for Christians MPs to be able to vote on matters of conscience freely due to safety concerns, as freedom of religious belief appears to be being continually eroded. This is currently a police matter and I would be grateful if people could respect my family's privacy."
The Society for the Protection of Unborn Children (SPUC) condemned the threat of violence against Dr Cameron.
Spokesperson Michael Robinson said: "Lisa is a valiant MP who has spoken out fearlessly in defence of unborn babies. Lisa needs our support and our thanks. As a society we must respect and defend freedom of conscience."
SPUC has sent her a bouquet of white flowers, inspired by the White Rose non-violent resistance movement in Nazi Germany, and is encouraging pro-lifers to get in touch with the MP to show their support.
Mr Robinson added: "Once again Dr Lisa Cameron MP has been targeted with hate and intolerance because of her deeply held belief that everyone deserves the right to life. It is especially despicable to target her through her family.
"Vilification is now routinely used as a tactic by pro-abortion advocates to crush debate and invite hateful attacks on those with a differing opinion. Those who believe in democracy need to expose the culprits responsible and defend genuine democratic values."