Routers and dot in string parameter

map.page ‘:sex/:word’, :controller => ‘say’, :requirements => { : sex =>
/girl|boy/ }

So this works fine:

http://mypage.com/say/boy/hello

also this:

http://mypage.com/say/girl/hello%20world

but this:

http://mypage.com/say/girl/hello.world

returns: Error 404 The page you were looking for doesn’t exist.

How can I fix this?