Sheldon Cooper is a theoretical physicist at Caltech who lives with his best friend, Leonard Hofstadter. Sheldon is known for his brilliant mind but also his quirky behavior and idiosyncrasies. Sheldon has a hard time understanding sarcasm and is, with the exception of his close friends and girlfriend Amy, uncomfortable with most social situations. Sheldon is extremely logical, but this comes at a cost of often being rude of condescending to others. Although Sheldon's friends are often the subject of his putdowns and narcisstic behavior, they have generally learned to live with Sheldon's quirks. Bernadette says that Sheldon doesn't know when he's being mean as "the part of his brain that should know is getting a wedgie from the rest of his brain".
Sheldon has many interests, including comic books, video games and sci-fi TV shows. Sheldon's favorite TV shows include Battlestar Galactica, Doctor Who, Star Trek and Firefly. Sheldon knows many languages including Finnish, Spanish, Mandarin, Persian and Arabic (and Klingon).
Although Sheldon does not enjoy the sport, he has a strong understanding of American football, thanks to his late father. When Leonard wanted to learn more about football to ingratiate himself with Penny's friends, Sheldon taught him football. When the guys spent Thanksgiving at Mrs. Wolowitz's house, Sheldon bonded with Bernadette's father, Mike Rostenkowski, over football and beer.
Sheldon generally avoids alcohol, drugs and caffeinated beverages, though he has made exceptions. Sheldon has been inadvertently drunk a number of times, usually at the hands of Penny. Sheldon voluntarily drank alcohol when he was nervous about giving a speech at an awards banquet. Sheldon also shared some beers with Bernadette's father, Mike, one Thanksgiving.
Sheldon's wardrobe includes a large number of superhero and other geeky t-shirts. He usually wears a different color long-sleeved shirt underneath his t-shirts.
Early Life and Family
Sheldon was born in Galveston, Texas, to Mary Cooper, a devout Evangelical Christian, and George Cooper, an alcoholic. Sheldon has an older brother and a fraternal twin sister, Missy. According to Mary Cooper, her two other children are "dumb as soup". Sheldon's father died when he was fourteen.
Sheldon has a loving yet complicated relationship with his mother, Mary. Although Sheldon greatly appreciates the love and support she gives him, he's uncomfortable with her religious beliefs. When Mary comes to town, Sheldon looks forward to her taking care of him as if he was a kid again. Despite his fondness for his mother's affection, Sheldon has at times longed for the sort of mother Leonard had in Beverly Hofstadter, a cold and distant mother with a brilliant analytical mind.
Sheldon speaks fondly of his grandmother, whom he calls Meemaw and who calls him Moonpie. Growing up, Sheldon's grandfather, whom he called Pop-Pop, was the person who most encouraged Sheldon's interest in science. Pop-Pop died when Sheldon was five years old.
Sheldon's academic brilliance started at an early age. Sheldon started college at the age of eleven and graduate at fourteen. He was, at the time, the youngest person to receive the Stevenson Award, receiving it at fourteen and a half. Sheldon received his first doctorate at age sixteen. He spent a year as a visiting professor at the University of Heidelberg in Germany.
Relationship with Amy
After Howard and Raj secretly set up an online dating profile for Sheldon, the website matched him with Amy Farrah Fowler, a neurobiologist. Howard and Raj blackmailed Sheldon into meeting Amy with the threat of a dirty sock. When Amy told Sheldon she only met with him because of an agreement with her mother to date once a year, and after she informed him that all forms of physical contact (up to and including coitus) were off the table, Sheldon offered to buy her a beverage.
After their first date, Amy and Sheldon texted each other for a few months. At the insistence of Penny, Sheldon and Amy went out on a proper date. Throughout this early stage of their relationship, Sheldon categorized her as a "a girl who is my friend but is not my girlfriend".
When Stuart asked Amy out on a date, Sheldon experienced feelings of jealousy and eventually recognized his feelings for Amy. After Sheldon interrupted Amy's date to convince her to stay with him, he and Amy officially become boyfriend and girlfriend with the signing of the relationship agreement. Their relationship grew closer when he cuddled an upset Amy after Bernadette and Penny left her out of wedding dress shopping. When the gang watched Howard's space launch on TV, in one small step for Sheldon, he grabbed hold of Amy's hand.
When Amy was sick with the flu, Sheldon took care of her as was his duty under the relationship agreement. Amy enjoyed Sheldon taking care of her so much that she pretended to be sick even after she had recovered. When Sheldon uncovered Amy's deception, he chose to punish her by spanking her. After Sheldon lied to Barry Kripke about having a sexual relationship with Amy, Penny asked him straight out whether he would consider a physical relationship. Sheldon told her it was a possibility.
When the whole gang played Dungeons and Dragons one evening, Amy got upset that the guys were mocking her relationship with Sheldon. Amy asked Sheldon if he thought their relationship will ever get intimate. Sheldon told Amy he doesn't consider their relationship a joke and that he would not rule intimacy out. Sheldon then played out the love potion scenario of the game with Amy, much to her delight.
For Valentine's Day, Amy arranged a romantic weekend trip to Napa Valley aboard a vintage train. After Sheldon spent the journey with a fellow train enthusiast, Amy confronted him about his behavior. Sheldon made Amy admit she "manipulated" him with the perfect trip in pursuit of romance, so Sheldon sarcastically gave her the romance she wanted. Sheldon drank wine, stared into her eyes and then kissed her. Though he intended the kiss to be short and sarcastic, Sheldon lingered and seemed like he may have enjoyed it. When Sheldon spent Anything Can Happen Thursday with Penny, she took him to see a psychic. The psychic told Sheldon all his issues, personal and professional, would be solved if he commits completely to Amy.
When the girls decided to recreate their proms on the roof of the apartment building, Sheldon was worried Amy might be expecting an intimate evening, as is Sheldon, who didn't attend his high school prom, was eager for his first prom to go well and chose to embrace all traditions associated with prom. When Sheldon picked Amy on the night of the party, he was overwhelmed and told her he couldn't go. Sheldon later admitted he was worried that Amy would be expecting them to get intimate after the party. Amy told him that she is always hopeful for something to happen, but that she just wanted to have a nice time. When Amy tried to tell Sheldon something, telling him he shouldn't feel any pressure to say it back, Sheldon jumped in and said "I love you, too." Sheldon told Amy there is no denying he has feelings for her that can not be explained in any other way.
Sheldon upset Amy when he revealed he had signed up for a one-way trip to colonize Mars without even discussing it with her. Although Sheldon didn't initially understand Amy's anger, he later asked her if she would like to submit a joint application for them both to go to Mars.
Sheldon's best friend is Leonard, with whom he shares an apartment. Although Sheldon can be dismissive of Leonard and his accomplishments, Sheldon is very dependent on Leonard as a friend and a roommate. Leonard is put upon to handle many chores for Sheldon, including driving him about. Sheldon sometimes overlooks the sacrifices Leonard has made, such as not living with his fiancee, to accommodate Sheldon.
Sheldon has occasionally shown a softer side towards Leonard. When Sheldon heard Penny might be considering dumping Leonard, Sheldon asked her not to hurt his friend. When Leonard moved out of the apartment because of Sheldon's annoying behavior, Sheldon tried repeatedly to get Leonard to return home. Sheldon was very concerned for Leonard when he needed minor surgery.
Sheldon initially took a disapproving attitude to Leonard welcoming Penny into their social group, though he has since come to value her as a friend. Sheldon has shown appreciation for Penny when she's cared for him when he's sick or taken him in when he's locked out of his apartment. Sheldon has returned the favor by driving Penny to the hospital when she was injured.
Sheldon saves much of his condescension and scorn for Howard, whose career he looks down on with great pleasure. As a result of Sheldon's antagonism towards him, Howard has not been as tolerant of Sheldon's quirks as the other guys. Sheldon views himself as Howard's slightly apathetic tertiary friend and described Howard as a treasured acquaintance, rather than a friend. In an effort to improve their friendship, Howard invited Sheldon along to see him give a speech at NASA in Houston. When their plane was hit by turbulence, Howard and Sheldon apologized to each other for their past behavior.
Sheldon and Raj's friendship has also seen its share of drama, particularly when Sheldon offered Raj a job working with him.
Sheldon was offered the opportunity to conduct a three month expedition to the North Pole to study monopoles. Despite their initial reluctance at spending three months in a ice cabin with Sheldon, the other guys accepted Sheldon's request to accompanying him there. When the guys returned from the expedition, Sheldon was upset to learn the guys had manipulated his data with an electric can opener. Having already publicly announced his results, Sheldon returned home to Texas in shame. The guys flew out to pick him up and, when Sheldon got tired of his mother's religious views, he returned to Pasadena.
Sheldon thought he discovered a technique for creating a new heavy element and was pleased when a Chinese research team reportedly tested his technique with promising results. Sheldon soon realized he made a mistake and was uncomfortable being praised for his accidental discovery. Leonard later disproved Sheldon's discovery, forcing him to retract his findings.
After Sheldon grew frustrated at his lack of momentum in his string theory research, he decided to switch field and chose to focus on dark matter. Sheldon was angered when the university refused his request to switch his field of study. The university's refusal was one of the reasons that led to Sheldon leaving Pasadena on a cross-country train journey. When Sheldon returned to the university, they found a solution to allow him to change his research as long as he teaches a class as a junior professor.
Raj: I don't like bugs, okay? They freak me out.
Sheldon: Interesting. You're afraid of insects and women. Ladybugs must render you catatonic.
Sheldon: Scissors cuts paper, paper covers rock, rock crushes lizard, lizard poisons Spock, Spock smashes scissors, scissors decapitates lizard, lizard eats paper, paper disproves Spock, Spock vaporizes rock, and as it always has, rock crushes scissors.
Sheldon: Why are you crying?
Penny: Because I'm stupid.
Sheldon: That's no reason to cry. One cries because one is sad. For example, I cry because others are stupid, and that makes me sad.
Sheldon: May I say something?
Leonard: Not right now, Sheldon.
Sheldon: But I think it may be comforting.
Howard: No, it's okay. What?
Sheldon: When I lost my own father, I didn't have any friends to help me through it. You do.
Sheldon: I'm not insane. My mother had me tested!