SWISS ARMY KNIFE
Male, because even though it appears useful for a wide variety of work, it spends most of its time just opening bottles.
Female, because they always go to the bathroom in pairs.
Male, because it goes bald and often is over inflated.
HOT AIR BALLOON
Male, because to get it to go anywhere you have to light a fire under it... and, of course, there's the hot air part.
Female, because they are soft and squeezable and retain water.
Female, because it is always getting hit on.
Male, because it is usually unpolished, with its tongue hanging out.
Female, because once turned off, it takes a while to warm up. Because it is an effective reproductive device when the right buttons are pushed. Because it can wreak havoc when the wrong buttons are pushed.
Male, because they hold everything in, but you can always see right through them.
Male, because it uses the same old lines to pick people up.
Female, because over time, the weight shifts to the bottom.
Male, because it hasn't evolved much over the last 5,000 years, but it's handy to have around.
Female...Ha! You thought I'd say male. But consider, it gives man pleasure, he'd be lost without it, and while he doesn't always know the right buttons to push, he keeps trying.