This approach analyses the rights and obligations generated for those who register as fathers, looking for concepts that have become embodied over time and causing a legal phenomenon called multiparenthood. The simultaneous possibility of having more than one father on your record brings major changes to family law, such as socio-affective paternity. This is breaking down factual paradigms and enabling anyone to enjoy full civil rights and have this capacity. The configuration of new families formed by a current concept of family entity, in the exercise of mutual tolerance in traditional family compositions, shows that affection goes far beyond the obstacles formed by the prejudice often faced in society, emphasising the obligations arising from registration. With this in mind, authors and jurists seek to debate the issue. I am very honoured that my modest degree has led to this work, which I am delighted to share.