Dr Brenner isn’t actually Eleven’s father and ‘Papa’ is simply the name he is known to her by. It seems to be Brenner’s way of making himself appear more friendly to her and the other subjects.
Eleven’s mother was a college student called Terry Ives (Aimee Mullins), who decided to take part in the experiment in the belief she was helping her country during the 1960s.
She was dating fellow student Andrew Rich and the young couple were very much in love.
While taking part in the experiment, she fell pregnant with Andrew’s baby and hoped she could withdraw as a participant.
Sadly, Andrew never met his daughter after he was shipped off to Vietnam to fight in the war, where he was killed in battle.
So it was Terry’s boyfriend Andrew rather than Dr Brenner who is Eleven’s father.
To make matters worse, Dr Brenner stole Terry’s baby after she gave birth and faked a miscarriage to hide the abduction.
Despite Dr Brenner’s best efforts, Terry knew her child was still alive and tried several times to get her daughter back, including suing the scientist and talking to the press.
When all failed, Terry’s last-ditch attempt saw her breaking into Hawkins Laboratory where she found Eleven in one of the rooms.
Before she could take Eleven, she was hauled away by the guards and Dr Brenner administered electroshock therapy on her to make Terry forget about Eleven but she never could.
Speaking exclusively to Express.co.uk, the author of Stranger Things: Suspicious Minds, Gwenda Bond, shed further light on the relationship between Dr Brenner and Terry.
In one scene in Suspicious, Dr Brenner asked Terry if she’s had sex, something she was hesitant to answer and seemed to allude to sexual interest on his part. However, Gwenda said these were among the real-life questions asked by the scientists carrying out MK-Ultra experiments at the time.
The New York Times bestselling writer did a lot of period research and she was also sent a book by the show runners Matt and Ross Duffer to help her further.
Gwenda said: “I was rooting it the screening questions they would have asked. I think one of the threads I wanted to tease out in the book was what it was like for women at that time and different kinds of women.”