A word of advice, manhandle the heck out of them right from birth. Do it every day. If you have kids let them do it every day. Take them from thier naps and let them nap with you on your desk while you work.
We had a feral, spitting, hissing vicious cat get pregnant with a stray male we had taken under our wing previously. Birth came around our house about two summers ago. We had five kittens. We kept the mother trapped in our garage during the whole time she was raising kittens. We could not get near her, ever. She would hiss and spit and bite us if we got near her. Her kittens, however were a different matter. We made friends with them and handled the daylights out of them. They would rush toward us every time we came into the garage, much to the consternation of the mother. They would even hiss at us (like mom) when they were coming over to say hi. They just did not know what hissing meant. Eventually, the mom weaned the kittens and it was time for her to go. We were tired of a mean, hissing spitting biting cat in our garage. We were not about to release such an animal out into the wild to get pregnant again. We called the city animal control to come and get the mother. (They had to use a net at the end of a long pole). We kept three of the cats as pets, and sent the other two to ASPCA to be adopted. The three cat we have are the MOST well behaved, docile cats I have ever seen. You can walk up to them, turn them over on thier backs and bury your face in thier bellies with no fear whatsoever. They DO NOT bunny kick, ever. They LIKE having thier bellies rubbed. They absolutely never use thier claws on us. I would trust them with a toddler playing with them without hesitation. They are about as dangerous as a stuffed teddy bear. They are more like dogs in the way they like to be petted. I am convinced that all the manhandling conditioned them to be this way. All three of the ones we kept are very similar in temprament.