The rule requires rape victims claiming tax credits for a third or subsequent child to prove they became pregnant as a result of an attack or while in a coercive relationship in order to qualify.
The policy has sparked a political row in Scotland, with First Minister Nicola Sturgeon describing it as “appalling”.
Scottish Conservative leader Ruth Davidson has said she supports the exemptions the UK Government has put in place on restrictions to child tax credits, saying she wants to see ministers “implement them in the most compassionate way possible”.
Around 300 campaigners attended a rally in Glasgow’s George Square on Thursday evening to call for the Government at Westminster to change its stance.
Addressing the crowd, SNP MP Alison Thewliss, who has been at the forefront of the fight against the changes, said no UK ministers have been able justify the policy to her.
“It is vile, it’s cruel and it stigmatises not just the women but those children too,” she said.
“Imagine how dreadful it would be to find out that that was the circumstances that you came into this world. The Government has no right to do that to children in this country. It is appalling.
“This Government has proven time and time again that they don’t understand domestic violence, they don’t understand the circumstances that women are living in.
“They need to know and they need to hear from people just how despicable this policy is.”
She added: “It’s not just the rape clause, they want to limit tax credits and the child element of universal credit to the first two children in a family.
“That says to people we only value those first two children, we make a judgment on the life that you live on the choices that you make - that is not acceptable in a free society.”
An estimated 300 protesters attended the rally in the centre of Glasgow.
Some of the banners held aloft at the gathering read: “Prove rape or suffer in poverty”, “In Scotland we look after each other”, and “Glasgow says no to the Tory rape clause”.
Sandy Brindley, the national coordinator of Rape Crisis Scotland, spoke out against what she described as a “horrific policy”.
She told the crowd: “If you think about the circumstances of somebody who becomes pregnant as a result of rape, to put them in the position where they need to decide about poverty or disclosing a rape to the Department for Work and Pensions, it is just unspeakable.
“I do not think as a society we can tolerate this. We need to be treating women much, much better than this.”
She went on: “What we’ve always known at Rape Crisis is that it’s a fundamental part of healing for rape that you have control over who you tell and when you tell.
“The last thing people want to be doing is speaking to someone in the benefits agency with no training at all in responding to disclosures of this nature.”
Mhairi Black, the SNP MP for Paisley & Renfrewshire South, also addressed the gathering, telling protesters: “This is a disgraceful, disgusting policy that will not happen on our watch.”
She added that opponents of the clause are “rightly disgusted that any woman has to declare and relive probably the most horrific event in her life all for the sake of a few pounds”.
Earlier, Ms Davidson said Ms Sturgeon will be guilty of “gross hypocrisy” if the Scottish Government does not act to bring in a new benefit mitigating the so-called rape clause.
She said Scottish ministers could use their new welfare powers to remove the need for the clause.