Beverly Hofstadter

Beverly Hofstadter is Leonard's mother. Beverly is a Neuroscientist as well as a Psychiatrist. Her parsonality (such as it is) is rather cold and, perhaps influenced in part by her professional life, overly analytical. She tends to diagnose the behavior of neruoses of those she's speaking to, Her matter-of-fact analysis of Penny's relationship with her father prompts Penny to burst into tears. Rather than attempt to console Penny, Beverly merely continued to psychoanalyze her. She diagnosed Raj with selective mutism and considered Raj and Howard's relationship to be an "ersatz homosexual marriage". often to their considerable discomfort. For example, Her primary interest is making accomplishments in her fields. At times, she seems to see other humans as merely test subjects and will ask those she finds particularly interesting if they would be willing to have their brain scanned.

Family and Relationships
As a biproduct of her personality, Beverly's relationships with others tend to be nontraditional in nature.

Leonard Hofstader
Beverly's relationship with her son is decidedly unmaternal. She frequently critiques various aspects of his life utterly oblivious to the fact that she might be hurting his feelings. Beverly mentioned at one point that Leonard's brother and sister are more successful than he is. Leonard's childhood with her can best be described as a series of neurological experiments. At one point Leonard indicates that he created a "hugging machine" in order to feel some sort of warmth and companionship.

Leonard's Siblings
Beverly noted at one point that her other children (Leonard's brother and sister) are far more successful than Leonard both professionaly and personally. However, there is no indication that she feels any differently toward them on an emotional level. When Penny remarks that she must be happy about her elder son's impending marriage to a sucessful young judge, Beverly replies "Why I'm not marrying the woman?"

Leonard's Father
We learn in the "The Maternal Congruence" that Beverly is divorcing Leonard's father, as he had an affair with a waitress. This is one of the few times we see anything resembling emotion from her as she indicates she "did feel something akin to grief and perhaps anger" and further characterized Mr Hofstader as a "loathsome son of a bitch". We also learn that they did not have a close romantic relationship with Beverly explaining that she had been responsible for my own orgasms since 1982 (perhaps a root cause for Mr. Hofstader's affair?).

Sheldon Cooper
Between her neurotically strict speech patterns, lack of social conventions, and attention to detail, she is basically Sheldon's female equivalent. Indeed, her inability to understand social conventions seems if anything to be somewhat more extreme and has to have some social concepts explained to her by, of all people, Sheldon (though his explanations typically reflect his own, at best, incomplete understanding).

It is therefore unsuprising that Sheldon and Beverly share an odd non-romantic attraction to each other. They have a mutual interest in having their brain scanned and have even sang a duet of the Journey song "Any Way You Want It". However she did once kiss him passionately while intoxicated (declaring afterwords that she'd "rather have the busboy"). She apologized the following morining, and Sheldon accepted as she was intoxicated (he blamed Penny).