Though it was rushed it's actually not that unsual for people get / married have children in times of conflict. Sirus made the statement that its a war that was beginning and even in real life wars produce marriages and children due to the emotions that are created.

Also I am not sure if anyone else has made the connection but do you get impression that Ted is just a younger version of Harry.... He has no living family other than Harry who is his Godfather, a Godfather.