All the Dragons we have met so far are apparently males. But what if there are female Dragons? I mean, the Dragons once ruled the world for...who knows how long? Wouldn't the Dragons have some way to reproduce?
I know that all Dragons are immortal, but I'm sure that even the Dragons were so numerous when they started out. Akatosh couldn't of just snapped his fingers and there was a thousand Dragons!! No, I bet he created a couple of Dragons (some male, some female), and then they multiplied into what they became.

The first response would be that dragons don't reproduce like the Daedra they are eternal and simply spring into existence. So they don't need a gender. I can't recall ever seeing a female Dremora. Of course despite the fact that daedra don't reproduce some varieties to demonstrate genders such as Golden Saints and Dark Seducers.

The second response would be how do you know some of those dragon's aren't female? Aside from three named dragons none of them are referred to as "him" or her.

They have no gender. They just are.

In lore, the only female dragons I believe are the Jills and they are with Akatosh maintaining time.

Many People, including Myself believe that Jills are Female Dragons, they only mend damage to the flow of time and rarely appear outside of Dragonbreaks. I do not think Dragons in TES are meant to reproduce.