Thank you! I found a developmental optometrist in town, and I think we're going to make an appointment with her. Ds identifies the letters correctly in isolation, even when I write p,b,q,9,p,P,g all in a row. He can distinguish between them. If he's reading a word with those letters, he doesn't get them confused. It's just when he's writing them that he sometimes reverses them. He writes a mirror image of the letter or number. Again, he doesn't do it all the time. We did go through a period where he didn't do it at all, and now all of a sudden he's doing it a lot. Anyway, we'll see what the DO says. Hopefully it's nothing, but I'd rather know for sure. Thanks for all of the advice and recommendations. I'll let ya know how it goes!