Berry tasty!
Ha, I always wondered why it took so long for Epilogue!Harry and Ginny to start breeding like Weasleys. This is a perfect explanation. And much better than the Epilogue in every way.
I want to think now that Harry later realized the real reason he couldn't have children, and it had nothing to do with what mengberries can cure. Although his childhood fantasy may have wanted Ginny, his body wanted Snape. :D
Great story! Extra points to Gryffindor The Severus Snape Endowed Chair in Advanced Potions Research for staying within canon. While improving on it.