The Supernatural lore spread out over the fifteen seasons that it ran for is incredibly expansive and can sometimes be hard to keep track of. However, one thing that had been constant for the Winchester brothers was their no-holds-barred, on-the-road lifestyle as hunters. Even though both brothers have had romantic relationships throughout the 15 seasons, none of them were permanent enough to force them to settle down.
Knowing this, it would be extremely surprising if you were to find out that Dean Winchester actually had a kid in Supernatural, and it's not Ben, Lisa's son. The child that we're referring to is Emma, a girl born to Lydia, an Amazonian, in the seventh season of the show.
Was Emma Dean's kid in Supernatural?
In Supernatural Season 7, Dean and the audience get the biggest surprise of them all when a teenager knocks at his door asking for his help, claiming to be his daughter. Season 7, Episode 13, titled The Slice Girls, turned out to be a strangely emotional ride for Dean.
The brothers come to Seattle to investigate a case where four men have been killed, their hands and feet cut off, and a strange symbol carved onto their chests. Sam leaves to do some research on the murders, while Dean ends up at a bar called The Cobalt Room. Here, he meets Lydia, and they end up getting together at her house.

As the brothers continue researching the deaths, they figure out a strange pattern where each of the men who were killed had flings with women they'd met at The Cobalt Room and were later killed brutally. Dean goes back to Lydia's house to retrieve a keepsake he'd found earlier, only to find her daughter, Emma, a toddler, when he sees her. However, suspiciously enough, by the time he leaves, he spots Lydia handing over a girl who looks to be five to a group of women and calling her Emma.
All of this comes to a head on Supernatural when they figure out the myth of the Amazonian women. It is revealed that, according to the myth, the Amazons are a tribe of female fighters, born to Harmonia and Ares, who needed men just for the act of procreation. Turns out, the Amazonian women, in a blessing from Harmonia, had powers that allowed them to procreate a female warrior who aged extremely quickly in not more than 36 hours after the act of impregnation.
As Sam leaves to try and untangle the mystery, Emma, now a teenager, knocks on their door and tries to convince Dean that she needs his help to get away from her mother and the rest of the tribe. However, as it turns out, this was a sob story that she was telling him before pulling out a knife to kill him. Dean, however, is already prepared and pulls his gun on her.

However, at the end of the day, she was his daughter, and he was unable to pull the trigger and tried to convince her to walk away. Emma goes on to point out that she knows he can't kill her, or he would've already done so. It almost looks like Emma is right, and Dean might be in grave danger owing to his three-day-old paternal instinct, but just then, Sam barges in and uses the element of surprise to his benefit, shooting Emma in the chest and killing her.
The possibility of witnessing Dean with his child was cut short just as soon as it was planted into the Supernatural lore, but nevertheless, imagining Dean as a girl-dad is a pretty interesting concept.
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