Maybe it's a knee-jerk reaction. You're confronted with a woman many months pregnant, and before you know it, your hands are all over her body trying to discern if that lump is the baby's knee or its butt.
But let's step back for a moment, and take the pregnancy out of the equation. It kind of looks something like this, doesn't it?
...Or maybe this?
Definitely at least this...
Some pregnant women like having their bellies rubbed. Some do not. There's a super easy way to find out though...
On the next edition of "ways people become borderline insane around pregnants:" “OH MY GOD, ARE YOU SURE YOU’RE NOT HAVING TWINS?!”