I remember there was apparently a scene cut when David first became the doctor where he explains to Rose that his regeneration was based on her. I heard there was something of a line such as 'like a chicken to an egg' (my memory is fuzzy). So now we have the doctor's daughter who looks like the offspring of Rose and the Doctor but we now know that its not through 'traditional' means. If the doctor reproduced a girl through this body using a reproduction machine it would stand to reason she would bear a resemblance to Rose because that is who the doctor's form is based on. This may be touched on in the episode hence the guy who read the Sunday Herald implying Rose was somehow involved. (or he could have been mistaken).