Another interesting question is this, as a father would you force it on your child to also fan the same club you're a fan to, or you will allow him be himself to fan any club of his choice even if it's your most rival club of all times.
What if your child is not interested in sports at all, or interested in a different sport asides the one you are interested in? you cannot make sure your preferences are your child's preferences too, that is wrong upbringing. Expose children to various choices, so they make the choices that their hearts incline to. It can be a very boring for a father who love sports to have none of his children interested in the same sport as his, but that is a reality you have to face.