To love other people's children was related simply to love the friends that have been with us in the time of our life that we have, it is true, we sometimes invite a friend to lunch, we invite him a beer, and so on.
I have always said that a child is the greatest blessing that God gives us, there are people who can not have children because of problems of sterility that they bring from birth or due to some illness they got in a certain time.If we love our friends whom we reach out with when they need us, then why do not we love our partner's children if they are single mothers or single fathers?