DNA²

In the future, the world's overpopulation problem is traced back to Junta Momonari and his supernatural ability to seduce women, which gains him the title of "Mega Playboy". Though you'd never know it, since currently Junta's powers have not woken up, and he's just your typical Unlucky Everydude with a literal allergy to women... that causes him to throw up whenever he sees a naked girl that isn't his mother. Which happens in front of Tomoko Saeki, the most beautiful girl at his school.

Right after this hilariously horrible incident, an Action Girl named Karin Aoi travels back in time to "assassinate" his ability by shooting him (non-lethally) with a special bullet that alters his DNA before his powers as Mega Playboy come to the surface... Unfortunately, it turns out she had the wrong bullet, and Junta's powers awaken with a vengeance.

Now Karin has to find him another way to control Junta's powers, or face the death penalty. While waiting for new orders from her superiors, she stays at Junta's home to keep a watch on him and learn about his environment (and the girls who could be affected, like Tomoko), and then she meets Ami Kurimoto, Junta's Unlucky Childhood Friend who is the only girl who is immune to the Mega Playboy's charm. Now she has to see what to do before Junta breaks havoc among the female populace!

Originally a short-lived early 1990s manga by Masakazu Katsura (the same author as Video Girl Ai), later adapted into a Twelve-Episode Anime. Its plot and characters also formed the basis of a famous Newgrounds Dating Sim called SimGirls.

Tropes used in DNA² include:

• Action Girl: Karin, Rurara.
• Anime Hair: Junta, to the ridiculous level of spiky hair.
• Bitch in Sheep's Clothing: Tomoko initially comes off as this, but she's actually incredibly lonely to the point of being a Woobie.
• Easily Forgiven: Tomoko, to her Jerkass boyfriend Ryuuji.
• Disappeared Dad: Junta's father died when he was young, so he was raised only by his Apron Matron mother Chiyo. Tomoko's dad works outside of Japan.
• Fartillery: Kotomi's... uhm, biggest problem. She farts when she gets nervous, and since she's a gym practitioner. . .
  • It should be noted that her farts in the manga seem to venture more toward Fartillery territory than the anime; in the anime, her farts are average sounding but in the manga they're often drawn like explosions to emphasize their volume.
• Gasshole: As mentioned above, poor Kotomi's disorder turns her into this when she gets nervous (which happens quite frequently) making her one of the rare female gassholes in fiction.
• Jerkass: Ryuuji. Even more after he gets shot by Karin by mistake, too, and gains powers from that.
• Important Haircut: Kotomi has Girlish Pigtails, which she later trades for a cute pageboy style.
• Karma Houdini: Okay, so Ryuuji ends up in the hospital and then gets Brainwashed and Crazy... but what about the several cases of attempted murder along with attempted rape?!
• Lonely Rich Kid: Tomoko's Freudian Excuse. Not only her dad is a very rich businessman who spends more time abroads than with his only daughter, but her mom is dead.
• Names to Know in Anime: Actually has a wonderful Japanese vocal cast: Keiichi Nanba (Junta), Megumi Hayashibara (Tomoko), Mina Tominaga (Karin), Hiroko Kasahara (Ami), Hekiru Shiina (Kotomi), Takehito Koyasu (Ryuuji), Sakiko Tamagawa (Rurara).
• No Badass to His Valet: Why Ami is the only known female actually immune to Junta's Mega Playboy persona.
• The Ojou: Tomoko
• Operation: Jealousy: Tomoko once asked Junta to go out with her to make Ryuuji jealous after a big fight. And it's right after the horrible (and hilarious) consequences that Karin comes in...
• Plot Hole: Rurara's existence is both this and a time paradox. First, Karin tells Junta that Mega Playboy only fathered sons and the trend continued down the line of only sons. Then, after the Mega Playboy gene is removed from Junta, Rurara doesn't disappear. The only logical explanation for this is that she was either his descendant through Ami or that being descended from Mega Playboy was a bluff.
• The Pornomancer: Junta is supposed to grow into this.
• Ship Tease/WillTheyOrWontThey: Junta falls for Karin pretty early on, and her wacky inner monologue reveals that she likes him even when he's not radiating distilled sexuality.
  • Either Downer Ending or Bittersweet Ending: In the manga, Karin seriously considers staying in the present with Junta, but when she realizes he's started to truly like Ami after all, she tells him she doesn't love him enough to give up being a professional badass, and says goodbye.
  • The anime omits all of this. Instead, she just tells Junta to be happy with Ami, and departs with a smile, leaving him fairly heartbroken.
    • Actually, the OAV's give a little more closure. After Mori is captured and Lulala is "defused", Karin again shoots Junta... but with a bullet that will both undo the MPB traits and erase his memories. Ami does beg her to reconsider it, asking Karin if that's really the best course of action, and Karin replies that it can't be really helped since she's from the future, her mission is fully complete, and there wouldn't be a way for them to really get together. She even cries as she explains this to Ami, who then accepts it and promises to make Junta happy; then Karin, Rurara, and the other people from the future return home.. Still Gecko, but makes a little more sense.
• Shout-Out: Mega Playboy mode Junta is very obviously based on the hair Gohan sported in Dragonball Z once he hit Super Saiyan level 2.
• Tsundere: Both Karin (Type B) and Ami (Type A)
• Vomit Discretion Shot: Even in the opening credits!
• White-Haired Pretty Girl: Karin