Bastardry
The term bastard refers to anyone born out of wedlock. In the Seven Kingdoms, there is considerable social stigma attached to being a bastard. The Faith of the Seven and that of the Old Gods of the Forest have rules against bastardy.
Bastards are not allowed to inherit their father's lands or titles, and have no claims to the privileges of their father's House. It is up to their father on how to raise or treat them: at worst they are unacknowledged and ignored, though they may fare better and be discreetly sent funds to ensure their well-being. At best, a lord will acknowledge his bastard children (allowing them to take on one of the special bastard surnames), but send them away to one of his distant castles to be raised away from his lawful family. For bastard children to be raised by their father in his own castle alongside his trueborn children is considered extremely unusual.
Faced with no prospects for inheritance, many noble-born bastards, even acknowledged ones, ultimately join the Night's Watch to seek fame and glory. The Night's Watch is much more egalitarian than the other institutions of Westeros, and at the Wall a man is given what he earns. Bastards who join the Night's Watch can rise to become high-ranking officers and commanders. Similarly, bastards may also take up the life of knighthood in the hope of being granted a place at a lord's household and even lands and titles for services to their liege lords. In this way a bastard may become the founder of a noble house.
There is no outright law punishing noble men or women for having bastard children, instead it is considered a social and religious disgrace.
It is possible for the king to legitimize a lord's bastard children, though this special dispensation is difficult to acquire and infrequently happens. It will usually only be granted if a lord has no other legitimate children (or no male children) to carry on the name of his house. However, the social stigma is not automatically removed after the bastard is formally legitimized.
