“My mother-in-law shaved my baby girl’s head while I was out shopping."

A mum got a shock when she came home from a shopping trip to find her baby daughter completely bald.

“My boyfriend and mother-in-law shaved my baby!” Alexandra58 posted on the US website Babycentre.

She explained that her boyfriend had brought up the idea of shaving a week earlier, suggesting that it would give their baby better hair.

“I called bull and refused,” she added. “Whether it works or not, I’m still upset he chose to do it without my consent and that his mum was a participant, since she’s already in the doghouse for coming over Christmas Eve and smothering her with kisses when she had the flu.

“My poor baby looks so funny and I’m amazed she sat through it.”

The mum says it’s a “cultural thing” for her boyfriend and his family, who are from Mexico.

“He apologised and admitted he was wrong for doing so but it was my mother-in-law’s idea since she gave him a new electric shaver for Christmas and he didn’t let me know because he knew I’d get mad and he wanted her to have pretty hair and he feels he doesn’t have a say in anything else.”

Perth-based hair science expert Simone Lee says it’s a myth that shaving a baby’s head will improve hair growth.

“There’s no scientific evidence or reason behind that theory,” Lee tells Mamamia. “Shaving hair will not make the hair grow any thicker or faster. The growth of hair depends on the follicles beneath the scalp.”

However, after shaving, a baby’s regrowth can look thicker.

“When babies are first born, their hair can be quite patchy,” Lee explains. “So by shaving the hair, when the hair does grow back, it’s quite even. To the eye, it would appear as though there is more hair, even though there isn’t.”

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She says in some cultures, shaving babies is a tradition.

“We do have people come in with that train of thought: ‘Will you please shave our baby’s head?’ We say to them that babies, especially when they’re quite newly born or even six months old, their scalp is very sensitive and their skin is very thin, so it’s not really good to do that, in that it could cause a bit of pain to the scalp, depending on how it’s done.

“The biggest thing is being careful.”