Sex strikes - a form of protest where a group of people, usually women, withhold sex to achieve a particular goal - have been a fixture in the public imagination ever since the time of the ancient Greeks.
“Join me by not having sex until we get bodily autonomy back,” the Charmed actress said on Twitter. “Until women have legal control over our own bodies we just cannot risk pregnancy.”
“A #SexStrike is a way to target straight, cisgender men so they may feel the physical consequences of our reproductive rights being systematically eliminated,” she added later in an opinion piece for CNN.
“This form of protest has the potential to raise the issue far beyond the usual groups engaged in debates about reproductive health. It's a way to ignite conversation and help everyone understand the gravity of the situation and the immediate need for swift action.”
Reaction to the proposed protest has been divided, with some suggesting it is just the sort of drastic action that’s needed, while others think it presents the wrong view of women and potentially ignores LGBT women.
One commenter said the strike made an important point about who controlled women's bodies.
But one person felt the sex strike proposal essentially ignored LGBT people.
And another was concerned it presented the wrong view of women's relationship to sex.
Meanwhile, some were in favour of the strike because, they say, it is a form of abstinence and could lead to fewer abortions.
US research psychologist Peggy Drexler, who studies sex and gender and has been vocal in criticising the sex strike, tells BBC Three that she thinks there are several problems with the idea.
“I think the biggest flaw is that a sex strike, as Alyssa Milano has called for, serves to reinforce the idea that women have sex in order to please men, or for babies only,” she says. “This strips women of any agency in sex whatsoever which, of course, is what she is ultimately arguing for women to have more of.”
Dr Drexler also points out that, “Certainly, Alyssa implied that the sex strike should be done in order to punish men, and of course not all women have sex exclusively with men.”
Despite the problems with the strike, however, Dr Drexler thinks it has helped focus attention on the issues at the heart of the campaign: “The strike has raised so much awareness that, even if it’s misguided, it’s calling our attention to what’s happening to women - we can’t just sit around and wish things were different.”
One of the earliest mentions of the idea of a sex strike is in the play Lysistrata, written by ancient Greek dramatist Aristophanes in 411 BC.
In the play, the eponymous character calls on women to stop sleeping with their husbands until they negotiate a peaceful end to the Peloponnesian War.
Nearly 2,000 years later, in the 1530s, Nicaraguan women were also reported to have used the tactic but this time to protest against the Spanish slave trade.
Women in the Central American nation were reportedly determined that their children would not be born slaves, and so launched a so-called ‘strike of the uterus'.
In more modern times, sex strikes have proved a popular concept around the world, including the famous attempt in 2003 by Liberia’s Leymah Gbowee, who mobilised women to campaign for an end to her country’s brutal civil war. One of her tactics was to suggest women withhold sex from their husbands and she went on to win the Nobel Peace prize in 2011.
Discussing the effectiveness of sex strikes, Leymah Gbowee has said that even though her suggestion was not necessarily put into practice, the threat alone proved useful in "getting people’s attention".
“Sex is an exotic thing, and many people would say it’s a taboo subject,” she told the Huffington Post in 2012. “But when someone dares to bring it to the attention of the public, it has two results. People start saying, ‘who’s this person doing this?’ and they start asking why the person is using sex to highlight an issue. And it gets men thinking... They start talking to their colleagues and beer buddies, saying ‘this war is wrong'.”
The publicity around the actions in Liberia inspired a number of similar campaigns, including in 2009 in Kenya when women’s activists began a week-long sex ban to protest against government infighting - even calling on the wives of the country’s president and prime minister to join them.
Patricia Nyaundi, executive director of the Federation of Women Lawyers, one of the organisations involved in the Kenyan campaign, told the BBC at the time: "Great decisions are made during pillow talk, so we are asking the two ladies at that intimate moment to ask their husbands: 'Darling can you do something for Kenya?'"
She added: "Even commercial sex workers should join in the campaign which is so vital to the country."
In 2008, the idea made its way to Europe when hundreds of women in Naples pledged to stop having sex with their partners unless they agreed to refrain from setting off dangerous and illegal fireworks on New Year's Eve.
And again in 2017, a Kenyan MP asked women to stop having sex with their husbands until they registered to vote.
Mishi Mboko, the women's representative for the coastal city of Mombasa, said, "Women, this is the strategy you should adopt. It is the best. Deny them sex until they show you their voter's card."
And it's not just politics. Sex strikes continue to inspire popular culture, including in Spike Lee’s 2015 Lysistrata-inspired crime comedy Chi-Rag, which features a sex strike by the girlfriends and wives of gang members to end violence in Chicago.
So while the debate rages on about whether sex strikes are effective, or even ethical, history shows this probably won’t be the last time we hear about them.