Are women's bra sizes different than children's?if so, HOW?

Is this a trick question?

I'm not sure, I just had this experience when buying my 10 year old daughter bras for the first time. I bought her a 32 in a children's bra and it fit her good. But then I saw some women's sports bras on sale (4 in a pack) for $9.99. So I thought I would by them since it was such a good price. I didn't see the since in paying $5 for one bra in the children's section when I could get a good deal in the women's section. She tried on the 32 bra's from the women section and they were to small. I had to go buy her sz. 34 (woman's). But these were sports bra's and the child's one was a regualar bra. The way it seems to me is they are about the same size but the women's have cup sizes. Not sure-new to me! Yikes...

Of course women's and children's bra sizes are different. The cup size is smaller, the chest is amller.