http://news.bbc.co.uk/1/hi/health/8394991.stm

Unfortunately, when it comes to being overweight, it's just cos I'm greedy and drink too much Coke - I'd be even fatter if I didn't walk over four miles a day, five days a week

Well it's good that parents will not be charged with abuse. However neglect cases should rise in proportion, and this gene not just used as an excuse for people or children being fat.

It doesn't matter if a gene makes you more prone to being fat. "Prone to" isn't the same thing as "will be".
Letting your children get obese is still wrong.

I'm not saying it's easy. Years ago children would walk everywhere, they'd think nothing of walking two hours across a city to do something or see someone. Now paranoia and PC pressure means parents are scared to let their children walk around the corner.
There is no way my son is going to have a TV or console in his room. Unlike some of his friends parents, we don't give him chocolate or crisps as a snack at the moment. We won't be taking him to McDonalds every time we go out, packed lunches will be the order of the day.

That would be my plan, if I ever have kids.