An expedition to Mars came to end. As the crew scrambled aboard, one of the crew members turned out to be missing. After a while the missing man appeared running from behind a tree, followed by a young and pretty Martian woman.

"Why are you late?" the commander demanded.

"You see, I made acquaintance with this lady, and she told me how they make children here on Mars. It turned out they just push a button on a computer, and if they do it once, they get a boy, and if twice, then it’s a girl.

Then she asked me how we do it on the Earth. I showed her, and now she is running after me and shouting, "Please, sell me your computer."