In a relatively small sample group, researchers found that women are attracted to men who like children. From Reuters:
In the study of nearly 70 men and women, an interest in children was linked to long-term partnership potential while women were attracted to men with higher testosterone levels as short-term romantic mates.
So, guys, if you think you're sexy, sorry. We will only use you for a fling. Now, if you like to play ball with the kids or will sit on the floor to play dolls or have a tea party, we'll let you stick around.