My son is 3.5 years old, 43", and 43 lb.  According to the sizing chart, I ordered size 5R for him.  I ordered both a Gray Straight Fit Jean 5R and a Black Original Fit Jean 5R.

There is a big difference in size.  The Straight Fit Jean is shorter and narrower than the Original Fit.  The Straight Fit Jean fits my son much better, but the top left corner of the brown leather label on the back is not stitched properly, which is unacceptable for a brand new unworn product.  This Original Fit jean is too long and the front and back rises are too high.

The waist bands do not adjust small enough, because even at the the max extension the jean is very loose around the waist and looks bunched up.  Although my son is at the lower end of the sizing chart's range for 5R, but I expected a setting that would work for him, since this size was suggested for him.  We do not have any problems finding pants for my son at GAP Kids.

I think this is an OK jean for the price.  Unfortunately, it did not work for us because of the issues with the length, overall size, and the waist bands not adjusting as expected.  I also was not happy with the severe sizing inconsistencies between styles.