---
title: "The Big Bang Theory"
chunk: 6/11
source: "https://en.wikipedia.org/wiki/The_Big_Bang_Theory"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T04:04:29.021226+00:00"
instance: "kb-cron"
---

=== Leonard and Penny's relationship ===
One of the recurring plot lines is the relationship between Leonard and Penny. Leonard becomes attracted to Penny in the pilot episode, and his need to do favors for her is a frequent point of humor in the first season. Meanwhile, Penny dates a series of muscular, stereotypically "attractive," unintelligent, and insensitive jocks. Their first long-term relationship begins when Leonard returns from a three-month expedition to the North Pole in the season 3 premiere. However, when Leonard tells Penny that he loves her, she realizes she cannot say it back, and they break up. Both Leonard and Penny go on to date other people, most notably with Leonard dating Raj's sister Priya for much of season 4. This relationship is jeopardized when Leonard mistakenly comes to believe that Raj has slept with Penny, and it ultimately ends when Priya sleeps with a former boyfriend in "The Good Guy Fluctuation".
Penny, who admits to missing Leonard in "The Roommate Transmogrification", accepts his request to renew their relationship in "The Beta Test Initiation". After Penny suggests having sex in "The Launch Acceleration", Leonard breaks the mood by proposing to her. Penny says "no" but does not break up with him. She stops a proposal a second time in "The Tangible Affection Proof". In the sixth-season episode, "The 43 Peculiarity", Penny finally tells Leonard that she loves him. Although they both feel jealousy when the other receives significant attention from the opposite sex, Penny is secure in their relationship, even when he leaves on a four-month expedition to the North Sea in "The Bon Voyage Reaction". After he returns, the relationship blossoms over the seventh season. In the penultimate episode "The Gorilla Dissolution", Penny admits that they should marry and when Leonard realizes that she is serious, he proposes with a ring that he has been carrying for years. Leonard and Penny decide to elope to Las Vegas in the season 8 finale, but beforehand, wanting no secrets, Leonard admits to kissing another woman, Mandy Chow (Melissa Tang) while on the expedition. Despite this, Leonard and Penny finally marry in the season 9 premiere and remain happy. By the Season 9 finale, Penny and Leonard decide to have a second wedding ceremony for their family and friends, to make up for eloping. In season 10, Sheldon moves into Penny's old apartment with Amy, allowing Penny and Leonard to finally live on their own as husband and wife.
In season 12, Penny announces that she does not want to have any children and Leonard reluctantly supports her decision. Later, her old boyfriend Zack and his new wife want Leonard to be a surrogate father to their kid since Zack is infertile. Penny reluctantly agrees to let Leonard donate his sperm. However, when she tries to seduce Leonard despite knowing he has to be abstinent for a few days, her visiting father, Wyatt, points out to Penny that her own actions suggest she is more conflicted over having kids than she lets on, and she admits she feels bad about letting him and Leonard down if she never has children. He says that despite her flaws, parenthood is the best thing that ever happened to him, and he does not want her to miss out, but that he will support her no matter what she does. Leonard eventually changes his mind, not wanting a child in the world that he cannot raise. In the series finale, Penny is pregnant with Leonard's baby, and she has changed her mind about not wanting children.