By force it definitely can. It happened today.
The firewire cable is designed with connectors that are shaped with a square on one side and a curve on the other. This is to prevent anyone from plugging it in the wrong way.
But please don't try this.
A student of mine did not notice the shapes and found it difficult to plug it in to the firewire port of the PC. So by force, he managed to squeeze it in. The wrong way round. Shocker! Idiot-proof?
OK. Nevermind, I'm a nice guy. Forgive him. The port is a little deformed now but still works.
HOWEVER, the poor camcorder "Babycam" connected to the other end of the firewire cable suffered the consequence. The reversed power polarity burnt and damaged its interface.
Babycam will have to go see the doctor and be hospitalised for 2 weeks.