Middle Children's Day --

Where a guy falls in his family order can have a huge effect on his personality and his role in your relationship, says Meri Wallace, author of "Birth Order Blues." If he's:

. A firstborn -- Bravo. You scored a dependable conscientious, and caring guy, one you can rely on for logical advice and support. But beware: If you don't speak up, this confident cutie can become a control freak.

. A middle child -- No doubt your dude has a way of getting along with anyone, thanks to his loyal, social, and sensitive nature. He's also really attuned to your feelings and super thoughtful. But as laid-back as he may be, he can demand lots of TLC and major reassurance.

. A baby -- The last of the litter tends to be a loving, outgoing, freethinking charmer. Your guy is likely a fabulous storyteller and great at cocktail parties. One caveat: He can be flaky, leaving you to make all the weekend plans.

. An only child -- You're dating a responsible and driven dude who'll be totally devoted to you. The downside? Since he never had to share his parents' love and attention or any possessions with siblings, he may be self-centered and possessive of belongings.