The latest Family Anatomy episode doesn’t appear in the iTunes store yet, and isn’t downloading for current subscribers. I’ve emailed Apple support, and I expect the issue will be resolved soon. In the meantime, you can find the (currently) “missing episode” here.
UPDATE: After searching through the code for the feed, the problem looks like it came from Libsyn. The episode now downloads on iTunes when you refresh your podcasts, but doesn’t appear in the store as I write this. Everything should be back to normal soon.