Too Real?

You know what I think would be a really interesting romance storyline. One that makes the father of a new baby that so many of them center around take a tests. Now that's realism for you. Maybe the reason things like that do not happen in romance novels is that it's too real. How far do you go in order to make a character, or story line feel real, without going over the line? I mean reading romance novels has always been a form of escapism. Who really wants the real nitty gritty involved? It could make for a great rom/com though.