Not the invitation exactly - the information sheet I'm emailing to people who say they are coming. I wasn't going to write anything about presents, as that's not why we're having a christening, but then I thought: people are going to bring gifts so isn't it sensible to try to steer them in the right direction so that we don't get (as happened at my son's birth and at Christmas) clothes that are too small or too big but inappropriate for the weather when he'll fit into them.
I was thinking about putting something like: please don't feel you need to get the baby a gift - we invited you because we want to spend time with you, and share our baby's special day. If you do consider giving him a present, however, clothes for 6-9 months suitable for the spring, or 9-12 months for the summer would be very useful.
Or maybe I just say - if you'd like any ideas for presents, please ask me.
Or perhaps I don't say anything and hope things that don't fit are returnable.
Advice greatly appreciated.