You all women know that no two brands have the same sizing chart!! So "What is your size for pants" will follow a next question: "WHICH brand???"
So far I can fit in size 10 for some brands (Old navy), size 13 for Lee's, and so on... I can get into smaller sizes (low as 8!!!) if I buy women's pants however if I want to wear snazzy juniors' pants, I have to go high (13, 15!) because the juniors' pants are designed for young women with *flat* butt... *think-- a walking stick!*
So yes, I am blaming it all on my big butt.
I doubt I can get any lower than size 10 due to my wide hips. I still can lose weight (in areas of... my butt and my thighs!) but my waist is skinny as it can go-- I can hurt people with my bony pelvic alone.

I learned last year when I went into this NICE fancy-schmany women's store (The Loft, I think) that the top does have it own sizing chart in numbers (not "S", "M", "L" etc)... so when I tried to figure out my size, I assumed the size for my pants was just the same as my top size so I took size 13 top-- and it was TOO BIG! So I tried on 11, 10, 9, 8 and It turned out that 8 was my top size...
I never knew that top and bottom are different. It just makes it difficult for us women to figure out our sizes for EACH brand, EACH piece of apparel and many more! Geez! Thanks a lot, Fashion!
I guess it could be because I grew up in the cruel world of juniors where I am accustomed being called "X-L", "size 15" .... I am SO glad to enter the REAL women's world-- Size 8, Size 10! WHEE!~
;-)