Am I missing something here?

[Mishy1234]

I have a GAP gift card from ages ago and have been looking online to see if there are any jeans for DS1 (3.5.). All the boy's jeans start at age 4 and the baby stuff stops at 24 months. What about 3 yo's? DS is quite short of leg, so he normally fits age 3 trousers atm.

Anyone with any experience of GAP sizing?

Look at their Baby Gap range.
It includes their Toddler ranges which go up to 5 years.

Do not order according to age. They rarely fit their age. DS was in an age five at 2 and DD in a seven at three! And my children are on the 50th percentile. Their clothes seem to be made for slender midgets. Best thing is to try a few things in store to see about the sizing for your children. Ironically I fit in age 14

I'd agree with two, Gap def.small for age but good for short-legged boys - I found the carpenter style were great for ds1 at that age.