there'll come a time when you'll have to tell them. i understand the apprehension, i usually don't say anything until a few weeks into employment, but most of my jobs have been structured a little differently than what you'll be looking for.
if you already have the job, then i suggest telling them as soon as possible. if you don't, do you think disclosure will affect you're chances at getting the job? if not, disclose right away. if so, i would wait until you have the job, then disclose asap.
with most of my jobs, cf might be seen as inabilty to do the work, even though it isn't. that's why i wait to prove myself before i clue them in. i would hope that your degree would speak for itself, and you should feel safer being up front with prospective employers. if kids are involved, any amount of deception, even if it's legitimate, might come acrossed against your favor.