I have always had problems gaining weight. I'm not exactly sure where i fall, but i'm a 19 year old male, 5'8 and barely hit 120. Somehow i've never had a G-tube and quite frankly i don't want one. When i was younger they put some sort of tube into my stomach but i was very young and therefore don't remember anything from it. it may have been a g-tube it might not have been. i don't know. At such a young age, I would think a g-tube would be good. she won't remember any of it (if it's painful or not I don't know..). I would ask your doctor if he thinks its time for one or not. he would know best (or at least he should!)