In January 1990, John Winchester met Kate Milligan in Windom, Minnesota when he came into the hospital where she worked as a nurse when he was injured in a hunt. Their son, Adam Milligan, was born on September 29, 1990 although he didn't have any contact with John until he was twelve. Thereafter, Kate and her son had sporadic contact with John who taught Adam pool and poker, took him to ball games on his birthday, bought him his first beer when he was 15 and taught him to drive The Impala.
Kate and Adam were killed by ghouls as revenge for the killing of their parent by John Winchester during the time John and Kate met. One of the ghouls took on Adam's form and memories in order to lure Sam and Dean to the town and later teamed up with its sibling in the form of Kate to finish them off. Both ghouls were killed by Sam and Dean.