Ziploc Bags are Male - they hold everything in, but you can see right through them.
Copiers are Female - once turned off it takes a while to warm them up again. It's an effective reproductive device if the right buttons are pushed, but can wreak havoc if the wrong buttons are pushed.
A Tire is Male - it goes bald and it is often over-inflated.
A Hot Air Balloon is Male - to get it to go anywhere, you have to light a fire under it (of course, there's the hot air part, too).
Sponges are Female - they're soft, squeezable and retain water.
A Web Page is Female - it is always getting hit on.
A Subway is Male - it uses the same old lines to pick people up.
An Hourglass is Female - over time the weight shifts to the bottom.
A Hammer is Male - it hasn't changed much over the last 5,000 years, but it is handy to have around.
A Remote Control is Female - it gives a man pleasure, he'd be lost without it, and while he doesn't always know the right buttons to push, he keeps trying!
A Water Faucet is Female - it can turn hot or cold in just a matter of moments.
A Safety Pin is Male - it is often useful in an emergency.
A Foreign Movie is Female - it is not always completely understood.
A Computer is Female - even your smallest mistakes are stored in memory.