Facebook was accused of encouraging care after the trial revealed that teenage girls are offered to middle-aged men as "suggestions of friends."
Young girls who join the social network receive up to 300 suggestions for whom to add friends, an investigation found by The Sunday Telegraph.
In some cases, suggestions apply to middle-aged men who are topless on their profile photos.
Facebook says it has safeguards to protect children, but activists warn that the company must do more to stop the caregivers who use the site to make friends with their children.
Andy Burrows, NSPCC Associate Head of Child Safety Online, said in The Sunday Telegraph: "Grooves are trying to penetrate into children's friendship groups on social networks, often with the intention of moving children to livestreaming or encrypted sites that make it easier for them to have sex abuse.
"Social media algorithms pose a risk that carers will find children more easily and make contact with them, and the recommendations" friend of a friend "or" new observer "may add relevance to their conclusions, which is why we call for blocking these functions for children.
"Too long social networks have failed to make their platforms safe for children, so the Home Secretary must commit to making strong and effective regulations to finally ensure that child safety is non-negotiable."
Facebook spokesperson said: "Care is extremely serious, and we have teams focused on ensuring the safety of children, thanks to extensive research and external experts.
"We use artificial intelligence to actively identify cases of inappropriate interactions with minors and refer to potential abuses to law enforcement agencies.
"We limit the way children search in search results, we remind them to only accept friend requests from friends and warn them before posting public posts."
Last month, Facebook said the company's moderators removed 8.7 million photos of children's nudity in the last quarter using pre-classified software that automatically marks these photos.
The machine learning tool implemented over the past year identifies images containing both nudity and a child, which allows to increase the enforcement of the ban on Facebook's posting of images depicting minors in a sexual context.
A similar system attracts users engaged in "grooming" or making friends with minors for sexual exploitation – the company said.