In the Toy Story movies, Andy's mother, Ms. Davis, causes everything that happens in the movies. She's the one who bought Andy all his toys and sets the entire series in motion. But very few people realize that she is unintentionally an anti-hero in the movies. In the original Toy Story (1995), she's the one who gave Andy the Buzz Lightyear action figure and also set the pointless you-can-bring-one-toy rule that sets Woody on a jealous rampage and almost made Buzz a satellite. In Toy Story 2 (1999), she tries to sell Wheezy at a yard sale. If she hadn't, Woody would have never tried to save him and Al would have never seen Woody and stolen him. In the most recent movie, Toy Story 3 (2010), she's the one who accidentally put the toys on the curb which made them think Andy was throwing them out.
Yeah, it's almost a good thing she probably won't be back for Toy Story 4, coming on June 16, 2017.
But there's something else to Andy's mom that I think is very reasonable: Andy's mom is Jessie's former owner, Emily.
Let's first take a look at what we know: Ms. Davis' first name has never been mentioned in the movies and Emily's last name was never mentioned either, so this is definitely possible. In all three Toy Story movies, we see Andy playing with his toys. While he plays with them, take a good look at the hat he wears.
As you can see, it has little resemblance to Woody's cowboy hat. But it does look familiar. Sort of like another cowboy/cowgirl's hat. Look familiar?
Here's the question to ask yourself: why would Andy wear a Jessie hat while playing with Woody? He was wearing the Jessie hat even before discovering Jessie. But there is something that sets Jessie's hat from the hat Andy wears.
Let's take another look at Jessie's hat.
This probably doesn't mean anything to you, yet. But when we hear the song, "When She Loved Me", which was basically the "Let It Go" of the 90's, I suppose, we see Emily playing with Jessie. She, like Andy, wore a hat.
Aha, the tables are turning now. While Emily plays with Jessie, she wears the same hat as Andy. The difference is the white lace on it, but of course, hats are going to get old as they age and the white lace is most likely faded.
What I'm trying to get at is Emily always played with Jessie as a kid. Then, she donated Jessie and had two kids named Andy and Molly. She bought Andy a bunch of toys and even gave her son her childhood hat so that he could wear it while playing.
And their ages line up, too. Toy Story and Toy Story 2 take place in the 90's and in Emily's room, we see a record player, which no one uses anymore.
This theory was developed by Jon Negroni. You can see his blog here.
It is plausible, but is probably not true. The co-director of Toy Story 2 and director of Toy Story 3 tweeted