i start with a female tepig it has 20 HP and if it is male it has 21 HP why? (dont trying to be ofending females that always hapened to me)
Males do not have more HP. The reason for this is that the male had higher HP IV's than the female tepig.
It could be EV's this will help you: http://pokemondb.net/ev
It could also be the IV's; http://pokemondb.net/mechanics/hidden
Meh, not true at all. It just depends on the IVs that the Pokemon is set with. It is that your male Pokemon just gets better IVs than your female Pokemon did. Nothing wrong with that.
It had started with more HP IV's then the female counterpart