Ziplock bags — Male, because they hold everything in but you can always see right through them.
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.
Kidneys — Female, because they always go to the bathroom in pairs.
Copier — Female, because once turned off, it takes a while to warm up. Plus, it’s an effective reproductive device when the right buttons are pushed. It can wreak havoc when the wrong buttons are pushed.
Tire — Male, because it goes bald and is often over inflated.
Hammer — Male, because it hasn’t evolved much over the last 5,000 years, but it’s handy to have around.
Remote control — Female. It gives men pleasure, they’d be lost without it and while they don’t always know the right buttons to push, they keep trying.
Hourglass — Female, because over time the weight shifts to the bottom.