The evolution of gender

If the first organisms such as bacteria do not have gender, then how did gender come about? How do we have male and female animals? How did it come about? Like was the first animal both sexes and then somehow he or she reproduced asexually until they...

couldn't reproduce asexually anymore, so they had to reproduce sexually with each other? Never been able to understand how it would be possible. Any ideas?

I dont think anybody can answer this
no one knows what the first animal was
animals have kept on evolving, dying out and changing, so its impossible to tell
we really only know about animals around jurassic period
anything before that is extreemely difficult to find
and everything that was around back then is gone, every single trace of them are gone
but asexual animals can change there gender
so there probably would have been ones that stayed a particular gender and vice versa, while other mixed sexes, it all depends on how and when they found a mate, and what sex they were

We accept the reality of the world with which we are presented.
- The Truman Show, 1998

It doesn't matter why or how, we just except what is. Although it is awfully fun to discuss and argue about such pointless things. Like religion and evolution and the colour of my socks.