Heather Crist Paley loved the private Facebook page where she could seek out advice from other mothers on such topics as finding a good nanny and the safety of raw milk.
There was only one subject she knew was prohibited — vaccines.
But when another member linked to an article on measles, the Los Feliz mother of two couldn't help but chime in.
Within minutes, Paley was banned.
As the national debate on childhood vaccines grows more intense, Internet forums such as Mommy2Mommy — gathering places for parents to discuss child-raising — are pushing back by restricting or banning the topic, sometimes banishing offenders.
"For the moment we ask you to refrain from posting about vaccines or measles," read an updated rule for the Moms of Inglewood and Surrounding Communities page. "It's a very heated topic that rarely gets debated but instead gets personal and even hurtful."
But for Paley and other young mothers who said they enjoy the free-flowing conversation, turning off the microphone feels like censorship.
"Everyone's all adults," Paley said. "They can handle themselves even if conversations do get heated."
The current measles outbreak has put vaccines back in the spotlight. Although the medical and public health communities are unified in their endorsement of vaccines, a minority continues to challenge that thinking.
The Internet is brimming with pro- and anti-vaccine sentiments.
There are "Vaccine Zombie" and "Immunize (Vaccine Anthem)" music videos. Articles are posted with headlines such as "Benefits of Contracting Measles" and "Harm Measles Can Cause Even Worse Because Its Preventable." And there are online order forms for "DNT VCN8" and "Fully Vaccinated" T-shirts.
For Los Angeles mother Michelle Turner, the online forums were a "lifesaver" as she navigated the many questions of raising twin girls.
So when Turner saw warnings that vaccine-related posts would be prohibited on Mommy2Mommy and Moms of Inglewood and Neighboring Communities she was infuriated.
"I like to read the different opinions," said Turner, whose daughters are vaccinated but who follows forums on natural alternatives for a range of issues. "I like to be educated and challenged in my thinking."
Another parent in the Inglewood Facebook group, who asked not to be identified because she risks being removed from the forum, said the restriction smacks of a misguided assumption that a group of "grown women can't have an intellectual conversation about this without attacking one another."
The woman, who is having her 4-year-old son vaccinated on a delayed schedule, said she considers posts about measles to be important health alerts, especially for parents of unvaccinated children.
"It's about being informed," she said.
Still, the conversations can grow caustic. As the number of confirmed measles cases ticked up in recent weeks, pro-vaccine parents increasingly vocalized concern — or anger — that choosing not to immunize harms the community overall.
The broad conversation has been "very ugly and very unpleasant," said Santa Monica pediatrician Dr. Jay Gordon, who advocates for parents' right to choose whether to vaccinate.
Gordon said that even some politicians have begun demonizing parents who question immunization. He urged pro-vaccine parents to try to understand the other side.
"Coercion doesn't work, shaming doesn't work," he said, speaking at a Hollywood premiere Wednesday for a vaccine-related documentary.
Orange County pediatrician Dr. Bob Sears, who recommends a delayed timetable for parents who choose to vaccinate their children, agreed.
"We do not need to hate them and ostracize them and, frankly, discriminate against them," Sears said of the sharp criticism of so-called anti-vaxers.
Sears posts a daily message on his Facebook account, which has more than 39,000 "likes," and said he will "ban the haters on both sides" if users' comments include name-calling or hurtful language.
Still, the tone of the language shows signs of degenerating.
"We can't get along because the anti vaxers are going to end up killing people! So if we put them all on one submarine and send them far away, that would be awesome!," one commenter wrote in response to Sears' post on why both sides need to "figure out a way to get along and love each other."
Another commenter wrote: "We don't take the claims from the flat earth society seriously because they are patently ridiculous, how are the claims from the anti-vaccine movement any less so?"
Even for Atlanta-based advocacy group Voices for Vaccines, conversations come close to "going off the rails," said Karen Ernst, who leads the group and oversees its Facebook page.
"No human was ever born with a needle in them!" wrote one Facebook user. "This guinea pig practice is rooted in Nazi Germany…Our mad medical regime has successfully hijacked the collective mind of our nation."
Ernst, a former classroom teacher, said she attempts to keep the conversation civil and on course by filtering out profanity, forbidding people to post just links and steering commentators back on topic.
"I don't want to turn away dissenting viewpoints, even though my perspective is that those viewpoints are not based in science," she said.
In the Los Angeles-area family forum Peachhead.net, founder Linda Perry typically moves lengthy or ugly threads about vaccines off the main page.
To her surprise, the topic hasn't been a problem this year, but she said commenters usually like to have the last word — an often futile desire in a group of more than 15,000.
"I feel like at this point you've heard everybody's opinion and it's never going to end," she said.
Aleigh Lewis, who said she was once "vaccine-hesitant," said she found reassurance in her decision to vaccinate her daughter after reading the posts from others on a Yahoo forum for Los Angeles-area mothers.
Lewis said she has continued to post messages in the group, hoping to reach those as wary of vaccines as she was.