If you’re going to put your children on your diet (whatever it is), you really have to ensure that they are getting the right nutrients otherwise you are just abusing them. It is the responsibility of the parent to realize that their diet lacks calcium and they should have figured out ways to replace it:

A girl of 12 brought up by her parents on a strict vegan diet has bee en admitted to hospital with a degenerative bone condition said to have left her with the spine of an 80-year-old.

Doctors are under pressure to report the couple, from Glasgow, to police and social workers amid concerns her health and welfare may have been neglected in pursuit of their beliefs.
The youngster, fed on a strict meat- and dairy-free diet from birth, is being treated at the city’s Royal Hospital for Sick Children. She is said to have a severe form of rickets and to have suffered a number of fractured bones. The condition is caused by a lack of vitamin D, which is needed to absorb calcium and is found in liver, oily fish and dairy produce.

(via)