Cosmo and Wanda (The Fairly OddParents); via Timmy's wish.
Ezekiel (Maria the Virgin Witch)
God (Christianity) chose the Virgin Mary to act at the mother of his son Jesus, who in actuality is Yahweh's vessel on Earth.
Jasmine (Buffyverse) was able to manipulate Cordelia and Connor's very lives so that they would copulate and give birth to her.
After being cast out of Heaven and reincarnated as a human, Ezekiel (Maria the Virgin Witch) chose Maria to become her mother.
Cherubs/Cupids (Supernatural) are tasked with pairing important bloodlines together...
...one Cherub that was known as Heaven's Cupid was particularly known for causing John and Mary Winchester to fall in love on Heaven's behest in order to conceive their sons, Sam and Dean to act as Michael and Lucifer's vessels during the Apocalypse.