Man of Steel, Woman of Kleenex

"Man of Steel, Woman of Kleenex" is a 1971 essay in which science fiction author Larry Niven details the problems that Superman would face in sexual intercourse and reproducing with "a human woman designated LL for convenience," using arguments based on humorous reconciliation between physics, biology, and the abilities of Kryptonians as presented in Superman comic books.

Publication history
The essay was first published in the men's magazine Knight in 1969 and then collected in Niven's 1971 collection, All the Myriad Ways.

In 1986, the essay was reposted onto Usenet; this led to what is thought to be the very first online report of copyright violation.

The essay was also reprinted in the 1990 Niven compilation N-Space.

A comic book-style adaptation—illustrated by classic Superman artist Curt Swan, and with all identifying logos and names removed—was published in a 1995 edition of Penthouse Comix.

Other uses
Many of the points given in this essay are reused and paraphrased in Kevin Smith's 1995 movie Mallrats.

In Frank Miller's comic Batman: The Dark Knight Strikes Again, Superman touches on the theme of the essay when asked about sex by Lara, his teenage daughter by Wonder Woman.

In issue 6 of The Boys, Butcher mentions that his human wife was killed when, after being impregnated by a super-human, the super-powered fetus kicked its way out of her abdomen.

Lois & Clark: The New Adventures of Superman normally avoided the issue, even during the titular characters' marriage. The exception was one case when Superman lost fine control over his powers due to red kryptonite exposure. In that episode, Clark accidentally gave Lois a bruise when hugging her, and did not dare to sleep in the same bedroom until the problem passed.

The television series Smallville also cited the same argument to explain why Clark refused to sleep with Lana Lang when he was in possession of his super powers. They were, however, able to be intimate when she also had super-powers in season eight. In the season nine episode "Escape", Clark tells Chloe that he has been learning how to control his powers so that he would not harm a human during intimacy.

In Garth Ennis's one-shot superhero comic parody The Pro, the title character gives oral sex to the Saint, a Superman caricature, after he saves her baby's life. At the point of climax, the Saint shouts "In God's name, move your head!" just as his ejaculation blasts through the wall, flies hundreds of feet in the air, and clips the wing off a passing airplane. The Saint saves the plane from crashing but is humiliated when the passengers realize he's still naked from the waist down.

A deleted scene from the 2008 movie Hancock illustrates a similar "dangerous ejaculation" scenario when Hancock throws his partner aside before his ejaculation blows three large holes in the roof of his trailer.

Tom Smith's "Superman Sex-Life Boogie" recounts the problem from Superman's perspective.

The 2012 graphic novel Superman: Earth One, Volume Two has Jonathan Kent trying to warn an awkward teenage Clark about sex, saying "Man of Steel, Woman of Kleenex. That's all I'm saying."