In many cultures we do not choose our family of orientation, so it may referred to as a "family we acquire by accident or random", so this is something over which we have no control at all. Instead, in a family of procreation we make the knowingly or informed choice of marrying someone with whom we become parents most of the times (this does not necessarily happens in countries like India or other ones where setting up marriages is common, or among Western royal families of the past). So, this can be summarized as the family of orientation not being the product of a willful choice, contrariwise to the family of procreation
