Photo Credit: ABC
Mark, Arizona, and Callie are finding that this whole three-person parenting thing can be difficult, especially Mark. They get into an argument about whether or not Callie should have an amnio, and Arizona and Mark fight about it all day while Callie just tries to avoid them and finally makes her own decision to have one.
Mark, who had been voting against, is actually fine with the decision, since Callie gave it some thought and didn't just side with Arizona; he points out that he just wants his 1/3 say in decisions since he's the baby's father and he intends to be a very present one. Arizona turns into a total brat about the whole thing, and it looks like Callie might be spending much of her pregnancy (and the next 18 years, come to think of it) as a referee, and she doesn't seem too happy about it.