Bought "men's" liner shorts by accident--does it matter?

[badgercat]

So my local Trek store was having a winter sale, and I found some nice chamois-ed women's liner shorts on sale for $9.99. I was so excited, I grabbed the one medium and one small they had left and tried them on. The small fit better. I bought them. I got them home and looked again--apparently the small, unlike all the other sizes I inspected, was actually "men's."

So here's my question:

What really is the difference between men's and women's cycling shorts? Is it just how they're sized? Is the chamois different? It seems wide enough for my sit bones, though unlike my spandex shorts, the chamois seems to be covered in like a brushed knit fabric. That makes sense to me considering the shorts themselves are a polyester/spandex knit, though. Or is this some kind of evil lady-crotch-burning fabric that no one warned me about, and I should return them post-haste?

I'm so totally clueless as far as cycling apparel goes... for the last four months, I've been wearing and washing the same one jersey and one pair of shorts every time I ride. I try to expand my options, and I just confuse myself. I'll probably freak out when my next pair of spandex shorts, which I ordered from the REI outlet, arrives... two options?? How will I know which shorts to wear when??