If I have a choice of parents, and a dietician is the most useful parent to have for achieving my goals, then yes, choosing a dietician for a parent is a rational choice. Of course, most of us don't have a choice of parents.

If I believe that children of dieticians do better at achieving their goals than anyone else, then choosing to become a dietician if I'm going to have children is a rational choice. (So, more complicatedly, is choosing not to have children if I'm not a dietician.)

Of course, both of those are examples of decisions related to the state of affairs you describe.

Talking about whether a state of affairs that doesn't involve any decisions is a rational state of affairs is confusing. People do talk this way sometimes, but I generally understand them to be saying that it is symptomatic of irrationality in whoever made the decisions that led to that state of affairs.