I ended up getting a woman's cycling jacket, because it was slimmer and quieter in the wind than a men's cycling jacket I'd tried. I'm not gonna be wearing multiple layers under the jacket, so I don't need a bunch of room. It doesn't look girly, and looks good. What is the difference between men's and women's clothes?

Men's usually broader across shoulders, women's some allowance across chest for boobs. Lots of pink colors available in women's. In sports clothes these can be very subtle, or non existent depending upon the maker. Some stuff is really unisex, but with different size tags for women and men (e.g., maybe a men's medium marked as ladies large, while really being the same).

If jacket/jersey is long enough, it might have some flare for hips. Like all clothing, there is a wide variety of clothing cuts and styles. Personally, I don't like pink and no flower decals or swirly lines on products either. It's frustrating to see pink and aqua jackets when what I really want is screaming yellow.

The main difference between men's and women's clothing is that men buy men's clothing and women buy women's clothing.
Men don't try on a jersey or jacket and ask their significant other if it is slim enough or makes them look fat.

Often times the way the woman's full length zipper starts is opposite the way it starts in men's clothing.

That's probably it, dkmatdrum. In some non-cycling coats, the only difference seems to be that women's have buttons on left.

Clothing for women is coated with a synthetic form of estrogen that vaporizes at speeds of over 12 m.p.h. and is inhaled by the wearer. You have been warmed.

I've got a rain jacket that turned out, unexpectedly, to be a women's. Short arms, zipper on the wrong side, a little baggy in places. I don't mind because some fitting issues are expected when you order cheap apparel direct from China. It still serves the purpose.

NB: Mens Jerseys, in pink, are the GC Prize, in the Giro D Italia.

Women's cycling tops assume a shorter wearer with wider hips that start with an abrupt flare instead of a gradual taper, so those intended to fit snugly don't work for men.

Sans middle-age spread (5'9.5", 135-137 pounds, 33-26-34 chest/waist/hips) I found most companies don't make men's tops small enough for pro-climber sized people, or at least don't sell them outside their custom program.

Desperate for jerseys which fit I tried a few women's models made for my measurements, and found they were way too big a few inches below my navel.

If you want decent fits, use the size charts instead of the labels (a guy with a 36" chest can range from XS to medium depending on company), and buy "race fit" not "club fit".

Ignore suggestions from people with different measurements - some brands allegedly tight in the middle actually aren't.