Parents are being investigated for possible child abuse because of the misinterpretation of guidelines on bruising in babies, it's claimed.
Official guidelines from health watchdog NICE for hospital workers suggest such bruising is very uncommon.
University of Central Lancashire research suggested the guidelines mean social services are investigating parents too often.
Its research said more than a quarter of babies are bruised accidentally.
One mother had her baby removed from her care for a year by social services, until its bruising was found to have been caused by a medical condition.
Lead researcher Prof Andy Bilson told the BBC's Victoria Derbyshire programme that "social workers are in danger of having to take decisions based on really misleading interpretations of research".
The NICE guidelines are used by local authorities to draw up their own policies.
Some 91 of the 152 councils in England have specific guidance on how staff should respond to possible abuse.
More than three-quarters (77%) of these do not give front-line staff such as nurses, health visitors and GPs the freedom to make judgements about the causes of a bruise, the university's researchers said.
In five local authorities, a formal child protection investigation must be undertaken when a single bruise in a pre-mobile child - who cannot crawl or walk - is discovered.
This is despite research from 2015 showing accidental bruising occurred in 27% of pre-mobile babies - those that cannot crawl or walk - monitored over a seven to eight-week period, researchers said.
Chelsea and Theo's story
Chelsea Kirtley had her baby Theo removed from her and the father's care for more than a year.
She initially took him to the GP worried that the bruising was a sign of meningitis.
But when further marks appeared, Stockton Council social services accused them of harming their child.
"It felt they were out to get us," Chelsea explained. "We got escorted by police off the hospital ward, with all the [other] parents looking at us."
Her son was placed into the care of his aunt, and then his grandmother.
The case was only dropped after Ms Kirtley had Theo examined by a geneticist, who diagnosed him with hypermobility syndrome - a condition that causes people to bruise easily.
But she says the stress caused her to split from the father and leave her job.
She was made homeless and now lives with Theo and her mother in a hostel.
The council said it "relied heavily on medical views throughout" its assessment of Theo, and that the safety of a child always has to be its number one consideration.
The tragedies of children such as Victoria Climbie and Baby P, in which warning signs were missed by social workers, are thought to have changed how local authorities deal with cases of bruising.
Labour MP Emma Lewell-Buck used to be a social worker in Sunderland, which has some of the strictest guidance.
"I never came across a case where a [pre-mobile] baby had a bruise, and that bruise was purely accidental," she said.
"I think you should always err on the side of caution."
She said the public would want social services to "do the right thing and make sure they had a full medical assessment to find out whether or not this was deliberate".
Prof Bilson acknowledges social workers have a duty to look into incidents of bruising, but said some parents would be put off from taking their children to see a GP for fear of being investigated - stopping the child from getting the medical care it needs.
"If this puts into people's minds even a hesitation of taking their child to a doctors, there's a real chance sooner or later some child will die due to this policy," he said.
NICE did not comment on the claim its guidelines could be misleading.
It said its original advice was aimed at medical professionals working in hospitals.
New guidance has been issued by NICE aimed more at social workers and teachers.
Watch the BBC's Victoria Derbyshire programme on weekdays between 09:00 and 11:00 on BBC Two and the BBC News Channel.