A bit random, but we have this legend. A man, a hero actually, was once carrying a mountain. Why he was, that is a separate story, but he was carrying a mountain on the palm of his hand.
While carrying it, he became so tired that a single drop of sweat rolled off
Besides this was such a long ago, I wouldn't be surprised if it turns out people of that time believed it was a mere coincidence that a baby is born whenever a man pokes his wife.
A sage had opened his eyes after meditating for a long time. Since he was pent up for so long, he ejaculated as soon as he saw a female fish. His semen fell on grass and made grass pregnant.
Not that exciting, but here goes. So we have this holy trinity thingy. Like, god of creation, god of preservation and god of death.
Once a person meditated for so long that god of preservation was impressed and gave him a boon. The man desired to watch god of preservation spooning god of death.
So god of preservation took a female form and seduced.
And had a baby too!