Gaia was the Greek goddess that represented the Earth. She was the Mother of All Things, human, animal, monsters, monstrosities and not least of all, nearly every other god. She was the grandmother of Zeus and also his great-grandmother (it's complicated). From Gaia came everything that was important. So she had to be fruitful and that basically involved in a lot of begatting and inter-generational knee tremblers to populate the planet.
Gaia was said to be the son of Chaos and Hemera. She married gaseous god Aether and by him had a son called Uranus who turned out to be real ban 'un. Gaia was always conscious that as more gods were created, her importance became less and she grew jealous of her family. In the end Gaia tried to even kill or imprison her grandchildren and let instead a parade of monsters to take over instead.
Gaia was always the difficult one at home. Her siblings were Nyx who was in charge of the night, The Fates who decided how much time you had on the mortal coil and Pontus, the sea. There was also 'Eros' - love but that post was later allocated to another God who changed his name by deed poll and became that manifestation. This is all conjecture as Gaia was poor at keeping records.
Gaia apparently started off this sibling sexual coupling by having it off with her brother Pontus. Earth and Water did mix in that case. By Aether she had the 'bad boy' Uranus. This was a particularly fruitful coupling - a entire race of gods, monsters and other beasties were the result. Aether later got a divorce and disappeared into thin air.
Relations with Uranus went south when he imprisoned his family. Concerned that she would be spending time alone, Gaia released her kids and got one of them Cronus to cut off Uranus's genitalia. Why Gaia insisted on that slight to her former husband/son isn't known. Cronus followed orders and Uranus disappeared up his own backside, never to be seen again. Only the late God's sex organs remained in hand - so Cronus threw those into the sea where some Greek jiggery-pokery led to the birth of Aphrodite. Since Pontus was the sea this would suggest Aphrodite was the consumated union of two male Gods.
For awhile (perhaps an eternity or two), this was the Golden Age. Cronus ruled the world with his sister-wife Rhea. Gaia was called upon for a few baby sitting duties and to keep an eye on her ugly brood which she had by Uranus. Gaia got more involved in her son-daughter's marriage when Cronus kept swallowing the grandchildren so it was her and Rhea who came up with the plan to substitute one child with a rock. This 'rock' stood in for Zeus who therefore grew up in safety - with a nanny goat and nymphs to keep him happy.
THe day then came for Zeus to come out in the open and he beat up his father and obliged him to disgorge the rest of the family. Cronus lost his throne but kept his tackle, being sent into exile. However Zeus didn't want his other uncles and sisters to bother him and sent them all back to hell.
Gaia was upset by this and urged her Titan boys to take on the 'Zeus gang'. They lost badly and were returned to prison. Gaia then produced forth a race of giants she presumably kept hidden away. They also got a beating until finally Gaia produced her major family 'black sheep', an enormous monster called Typhon who was her son by another of her brothers called Tarturus. Typhon almost succeeded in blowing the House of Zeus out of Mount Olympus but failed when he hit land and fell flat on the Earth.Zeus had him buried under Mount Etna where he still lurks today, belly aching about his fate and spewing out hate now and again.
Gaia was eventually reconciled to her grandson and settled down to making honey cakes and jam tarts. This was when she assumed the classic 'Earth mother' look with hips that were as wide as she was tall. Gaia apparently still had a few 'free children' from her past relationships but their disagreeable habits and looks tended to get them into trouble with Greek Heroes and die.
Gaia later on joined the Green Party where she has been an activist. She has threatened that if mankind doesn't change its way, she is going to kill off everything. So there.