Our initial motivation is to have sex. Breeding is a 'side effect'. Social pressures in the past few thousand years (an microscopic amount of time that the human species has existed) have encouraged 'breeding' in order to continue each 'tribe' or social group.
Me, I have no urge to 'breed'. While some people like to think their genes are superior to others and think that makes it more important that they have kids, I have no such delusion. Basically, all our genes 'suck'. We live, spend astronimical amounts of energy in the pursuit of reproduction, we die, and in general, contribute very, very little to the advancement of the species.