well you just proved your own theory wrong since she died as soon as she named him, not enough time for another kid to come out.
also
http://www.onemanga.com/One_Piece/551/05/ roger tells garp to protect his CHILD not his children
oh and
http://www.onemanga.com/One_Piece/574/17/ "gol d. ace. the name of our CHILD
Oda added the anne part for story-telling and for realism by doing what most pregnant women do, picking a boys and girls name. and he ends it all up by saying gol d. ace as a ta-da, the life and death of ace moement
and you didn't answer my question of what you think it is. tell me instead quoting mr. t