“Girls have breasts for two reasons,” the book, originally published 2013, stated. “One is to make milk for babies. The other is to make the girl look grown-up and attractive.
“Virtually all breasts, no matter what size or shape they end up when a girl finishes puberty, can do both things.”
Sharing a photo from the book on 27 August, Ragoonanan, who has a five-year-old daughter, wrote: “Wtf? From the Usborne Publishing book ‘Growing up for Boys’: ‘Girls have breasts for two reasons - for feeding babies and looking grown-up and attractive’.”
His post had more than 500 shares and attracted comments from other parents who were outraged by the wording.
“This is unacceptable. How can we officially complain about it?” wrote one person.
Another commented: “Never seen anything as bad as this. Breasts are not there for boys’ pleasure. And how awful for early-developer girls if this is what their male schoolmates are being taught.”
Speaking to HuffPost UK, Ragooanan said: “Teaching boys that a key purpose of a girl’s breasts is to be attractive to them and a sign of being grown up, i.e. sexually mature, is misguided at best.
“An educational book aimed at boys should be challenging the objectification of women, not amplifying it.”
Gender-neutral campaign group Let Clothes Be Clothes shared the dad’s post and wrote: “Seriously NOT OK Usborne Publishing - irresponsible, offensive and wrong, wrong, wrong.”
In a statement to HuffPost UK, a spokesperson for Usborne Publishing said: “Usborne apologises for any offence caused by this wording and will be revising the content for reprinting.”
Usborne Publishing have released a longer comment, available on their website.