Lisa the Simpson

"Lisa the Simpson" is the seventeenth episode of "The Simpsons" ninth season. It originally aired on the Fox network in the United States on March 8, 1998. In the episode, Lisa fears that she may be genetically predisposed to lose her intelligence after Grandpa tells her of a family gene that can permanently take away intelligence.
"Lisa the Simpson" was written by Ned Goldreyer and directed by Susie Dietter. This episode was the final episode with Bill Oakley and Josh Weinstein as show runners. 
It received generally positive reviews from critics, and is considered one of the best episodes of the ninth season.
Plot.
At Springfield Elementary, Lisa is presented with a brain teaser, which she is unable to solve. Following this incident, Lisa finds herself unable to perform simple tasks. Later, Lisa tells Grampa about her recent cognitive problems. He seems to recognize this, and tells Lisa about the "Simpson Gene", which apparently causes all members of the Simpson family to gradually lose their intelligence as they get older.
Lisa appears on the TV news program "Smartline" to tell the citizens of Springfield to treasure their brains. As she does this, Homer decides to prove her wrong, and contacts the entire extended Simpson family to visit. However, when they arrive, Homer realizes they are also unsuccessful, unintelligent people, which only depresses Lisa further and causes Homer to send them home.
However, before they leave, Marge urges Homer to talk to the Simpson women. Reluctantly, he talks to one of them at her request and he discovers that the women are all successful. Lisa asks why the women in her family were not affected by the "Simpson Gene". Dr. Simpson reveals that the defective gene is only found in the Y-chromosome and only the males are affected. As a female, Dr. Simpson tells Lisa that she will be successful like them. She is relieved that she is fine and she will not suffer the "Simpson Gene". When Bart realises he will be a failure in life due to his gender, he is wary and bemoaning his future. However, Homer reassures him that he will be a spectacular failure. Lisa is soon finally able to solve the brain teaser she was unable to finish earlier in the episode.
Meanwhile, Jasper visits the Kwik-E-Mart and attempts to empty the freezer containing ice cream in order to freeze himself, with the intention of being defrosted sometime in the distant future. Apu decides to take advantage of this unusual situation for financial gain, exhibiting Jasper as "Frostilicus". The convenience store, now renamed the "Freak-E-Mart", becomes more profitable as a tourist trap, until the freezer's cooling system fails, causing Jasper to defrost and walk away. Apu then decides to turn the Kwik-E-Mart into a nude nightclub called the "Nude-E-Mart".
Production.
This episode was the final episode that was run by Bill Oakley and Josh Weinstein, as it was a carry-over episode from season eight. The episode was written by Ned Goldreyer, and is one of the two episodes he has written on "The Simpsons". Susie Dietter, one of the directors of the show, also left the show after this episode, but returned for one episode in season 18, "Yokel Chords".
As it was the final episode they ran, Oakley and Weinstein wanted to end on a good note, with Weinstein stating that the episode "was meant to embody the humor, depth, and emotions of "The Simpsons"". They also wished to have an episode they ran that was based on the background of every character they could do, and believed that this episode came out well. The name of the episode was the center of an argument that Oakley and Goldreyer had, as Oakley had originally wanted to have the episode named "Lisa the Simpson", although Goldreyer wanted to name it "Suddenly Stupid", a pun on a show that had been airing at the time called "Suddenly Susan".
The Simpsons' family members that showed up took some time to be made, but the staff enjoyed the results. All of the male Simpson family members that showed up were voiced by Dan Castellaneta, the voice of Homer. He had asked for the recording tape to be run for about 20 minutes, so he could do many different voice variations that would fit the different men, but still be close to Homer's voice.
Reception.
In its original broadcast, "Lisa the Simpson" finished 19th in ratings for the week of March 2–8, 1998, with a Nielsen rating of 10.7, equivalent to approximately 10.4 million viewing households. It was the second highest-rated show on the Fox network that week, following "The X-Files".
IGN's Todd Gilchrist named the episode as one of his favorites of the ninth season in his review of the DVD boxset. The authors of the book "I Can't Believe It's a Bigger and Better Updated Unofficial Simpsons Guide", Warren Martyn and Adrian Wood, thought well of the episode, saying, "A terrific episode, with a good mix of pathos (Lisa's farewell to the Springsonian and her favourite jazz club are inspired) and fun (her Homeresque 'woo-hoo') which comes together to make a refreshing and exciting look at Lisa's life."
Bill Oakley and Josh Weinstein greatly enjoyed the episode and thought of it as a great final episode that they ran. On the DVD audio commentary, writer Ned Goldreyer stated, "I think this might have been the best episode ever produced."