Does a baby blanket have to be a certain size??

I know this is kind of a silly question b/c you can sew a blanket whatever size you want but is there a standard?? I am sewing up some baby blankets and using a velour backing but I just discovered I only have enough velour to make 25"X30" blankets, is this a wierd size? are all baby blankets usually square? I am making this as a gift so i of course want it to be perfect 

I think it would be fine.  Some smaller blankets are 30 x 30 and it's nice to have a different size for those times you don't want alot of bulk.  I say go for it!

I've crocheted many baby blankets that were 25 x 30. Thats a great size for a baby blanket.Everybody was always happy with them.

Just thought I'd say that I prefer a rectangular blanket - fits my cot, pram and stroller better!
My husband is laughing at me cause he thinks I'm daft for telling you that! Cheeky! But you did ask!
Ax