There isn't any proven reason as far as I know, but you know what, I would do it- I am gf as is ds1 and it is a pain, if I'd known then I would have had ds1 gf as long as poss- gf oatcakes, rice cakes etc are easy to do when they are so little.
DD is 5.5 months and starting to show interest in food so I'm planning to do BLW with her. Thing is, I'm wheat intolerant (blood tests for coeliac disease came back negative) and I'm reading that maybe I should seek advice/hold off wheat til she's 1? I think it's be fairly easy since I eat a GF diet anyway but DH wonders if it's necessary. Any experience/advice would be appreciated.