How bad is the karma of feeding meat to your children? I have a girlfriend who has a daughter from another man. If I raise this kid not vegetarian, will that be bad karma? Her mother is an omnivore and the kid is being raised in an omnivore household. It would be very difficult to change her diet. Is it my reponsibility to make her vegetarian?
Please read "Why is contributing to the market demand for meat not wrong?".

According to most schools of Buddhism, it is against the first precept to kill an animal yourself, but it is ok to buy frozen meat from the supermarket for consumption.

Let's say you go to a restaurant as a customer. If the restaurant prepares your meal order using frozen meat, then that's  ok. But if you have to select the animal for slaughter (which happens in some Asian countries, for seafood dishes for e.g. you need to pick your lobster from an aquarium), then that breaks the first precept.

As long as you did not do the killing yourself or select the animal and ordered the butcher or chef to slaughter for you, it is not a violation of the first precept.

To summarize from that question:


It is wrong to kill or directly cause the killing of animals
It is wrong to have a livelihood on the business of meat
It is wrong to consume meat that is from an animal that is seen, heard or suspected to have been slaughtered specifically for you
It is ok to purchase and consume meat from the market (that was already dead long before you arrived at the market)
It is ok to order a meal from a restaurant, which is based on frozen meat


Why? This is because you did not have the intention to kill that animal. You are simply buying meat that was no longer alive when you first encountered it.