target consumers:pros vs cons of having a specified market

This morning I ran an all-women's 5k. There was something really special about a race where every participant was a woman, but it was a little... restrictive too. Women from all over Cincinnati came to participate in the special race, but the fact that it was a women's-only event easily cut the participants in half. Is it better to cater a race exclusively to women (pink race shirts and jazzercise before the start), or just put on an excellent event and let everyone be a part of it?

This same question comes up in product design. My road bike is a trek WSD- women's specific design. I like that the proportions fit me better than a bike designed for a man, but more than one person has asked me what makes my bike so different (see the image above.) When does it make sense to design for a very specific target consumer, and when should the brief (design problem) be more broad? What makes any one segment (women) a potentially profitable specified market?

I think pride about being part of any given segment is a requirement before any product made specifically for that segment can be successful. What I mean by that is that I am proud to ride my women's-specific bike because I am proud to be a strong, fit woman.