When a young man begins shopping for panties it is most often local: Local being a hamper, mother's dresser, sister's, cousin, clothes hanger and etc. etc. etc. Shopping local leaves you with whatever you find and most often not exactly what you were looking for. Although there have been times, rare as they are, when breathing was difficult at best.
What strikes our fancy is as varied as the styles and types of panties you can buy. If you've shopped out there then you'll understand what that means. Ironically panties are one of the few things that have crossed the lines in society at large and I cite Hannes Her Way which is most often now cotton and Hannes His Way which is most often nylon. It also wasn't that long ago that anything other than white for a guy was the norm so things have changed even if it hasn't been fast enough.
Anyway girl's and women's panties are nothing like men's undershorts and isn't that a wonderful thing. They are styled much different and it begins with the absence of that ugly front panel. Other than adornment such as a panel of lace or applique panties are smooth in the front.
Girl's and women's panties are also more narrow in the crouch and the reasons for that is the same for why men need a cup for sports. Women also have smaller waist and larger hips proportionally than men. Because of that difference men's underwear is measured at the waist while a women's is at the hips. Actually a man can buy women's panties using that hip measurement as his "waist" measurement because the waist of a woman's pair of panties must go over those hips. That's also called "ease" or give and manufacturers allow for that "ease" in panties "elastic" for that reason.
Not long ago the only size given for women's panties was a single number in "panty size numbers" (most times) such as 3, 4, 5, 6 and etc. With three being smaller than four and so on. Of late that's begun to change in inches like men's as the baby boomer's move into retirement on the "plus" size. Girl's panties are most often measured by age such as size 1, 3, 5 etc.
Most often after size twelve the manufacturers give dress sizes or waist sizes in inches. Panties come in all sorts of styles and fabrics and if there is no other reason for cross dressing then I would put panties at the head of my list.