If this man acted as father to these children for 16 years, I see nothing unusual about this decision. The children must consider him "father". Gender of the judge has nothing to do with this.
in loco parentis
http://en.wikipedia.org/wiki/In_loco_parentis
This doctrine can provide a non-biological parent to be given the legal rights and responsibilities of a biological parent if they have held themselves out as the parent
This man would have a right to bring in the natural father (if he can be found) to off-set what he is paying.