My wife, who is blonde, came running up to me in the driveway, just jumping for joy!
She said, "Honey, I have some really great news for you!" I'm pregnant!
Then, she said "Oh, honey.  There's more. Well, we are not having just one baby. 
We are going to have TWINS!"
Amazed at how she could know so soon after getting pregnant, I asked her how she knew.
She said, "Well, I went to Wal-Mart and bought the twin-pack home pregnancy test kit 
and both tests came out positive!"