The two women that I know that purchased the Apple Watch Sport got the 42mm model. Its actually smaller in real life than it looks in the photos. When I waited in line at the first try-on session, I would have sworn the Watch on display in the Window was the 38mm, but the Apple employee said it was the 42mm. If your wrists are tiny, you'll probably want the 38mm, but for medium to large I would say 42mm. The 42mm of course has a bigger screen, but also better battery life. But the folks here are right... you need to go in and try one on. Its largely personal preference. I just wanted to chime in so you didn't assume that women should automatically get the 38mm.