That's an incredibly personal subject. Some people can develop such bonds, others cannot get past the perceived distance. The importance of bloodlines runs very deep in most western societies (I don't know much about other societies, so I won't generalize...), and simply saying it is possible ignores a lot of social stigmas and personal attitudes.
No, but the biological bond is started while the child is still in the womb. The child is born with a knowledge of the people around the mother from hearing them while in the womb. If I was in the office, I could site some recent studies, but they should be pretty easy to find. Talking into the belly looks dumb, but it is a pretty good idea for the father.
The bunch of traditional sayings and tales about stepchildren and stepparents aren't without a basis in reality. You don't neccessarily need biological connection to develop such bonds, but it does have a fairly strong impact and correlation.