I don't want to seem like a weird, presumptuous pervert or anything, but I'm going to just put it out there and presume that you are all perfectly capable of having sex, which is a lot more than the 7 superheroes below can boast.
Sure, they can punch through reinforced concrete and save the universe from evil, but these guys and gals are incapable of doing the dirty, which is what matters, right?
7. The Silver Surfer
The Silver Surfer might identify as male, but he is essentially a genderless and a-sexual being who can probably get sexual pleasure from a more enlightened method than the old in-out.
Or, in the much more eloquent words of Redditor periphery72271:
He was originally gender identified and genetically male when he was Norrin Radd and was heterosexually attracted to his monogamous mate, Shalla Bal.
Galactus transformed him into the Silver Surfer, and removed all emotions except those productive to being a Herald, so during that time he was asexual.
His genetics were unique and he had no reproductive capability, so his sex wasn't relevant, however he maintained his gender identification as male.
Once he met the Fantastic Four and specifically Alicia Masters, his emotional psyche was restored and he became reacquainted with the idea of love, and immediately pined for his own lost lover. Being that he was devoted to only her and thought her dead, he identified as heterosexual but remained celibate.
Eventually he would reconcile himself with the loss of his original partner and have heterosexual romantic relationships with gender identified females, such as Nova and Alicia Masters. He expressed the desire for physical intimacy, however he has never chosen to alter his form to accommodate those relationships, and it's not disclosed if any of those relationships were ever sexual in nature.
In all honesty, Nova, was, like him, a Power Cosmically transformed entity who had no need for physical sexual stimulation, and Alicia Masters had been the previous partner of Ben Grimm, for whom a sexual relationship was an impossibility, making her very likely accustomed to being celibate if not actively asexual herself. Sex likely wasn't really a critical issue for either of them.
The simple truth is that he has the power to accomplish any desired result that could occur from sex without actually participating in it, so there is really no need for him to simulate genitalia. He can generate pleasure within himself or others telepathically or via directly manipulating the brain and share the pleasure of others with cosmic awareness, so it's arguable if physical sex would actually even compare.
6. Ben Grimm a.k.a The Thing
Ben Grimm was a perfectly normal dude before the accident that changed him into The Thing, but that doesn't mean that all is well downstairs.
His transformation caused a massive physical disruption at cellular level, and although he maintains a human skeleton, musculature, and organs, his skin has become thick, warped and distorted.
The Thing's hide of rock like plates seems to have destroyed his extremities by causing his nose to shrink to a mere pebble, his ears to be totally swallowed and his fingers and toes to fuse into clubby stumps. This does not bode well for his genitalia...
Not to mention what he looks like without his signature pants in the 2015 Fantastic Four movie!
Rogue has a killer body, a bangin' leather jumpsuit, and a super hot boyfriend, but unfortunately this seemingly sextastic recipe is destroyed by the fact that she can't touch anyone. Ouch. It's further proved by this scene from the first X-Men movie.
Clearly the sexual frustration got a bit much for her because she gave up her powers in X-Men 3.
4. Bruce Banner a.k.a Hulk
The Hulk's boning abilities are entirely based on circumstance, but the fact that getting worked up turns him into an uncontrollably furious green beast with a dick the size of a bread bin does make things somewhat difficult.
While we all remember the memorable scene from the 2008 Incredible Hulk movie that involves a motel room and Bruce Banner unsuccessfully attempt at coupling with Betty, there are actually some exceptions in the comics.
Possibly the most memorable one being when Bruce's pathology is reversed, so he’s either a totally zen Hulk or a rampaging angry human, like that guy you avoid eye contact with in your local dive bar. In his “savage Banner” form, Betty has sex with him, and this calms him down. Who knew!
I admit it, I know nothing about Kurt Busiek’s Astro City apart from the handy tidbit that Beautie, the hot robot girl, doesn't just look like a Barbie... See the comic book panel above for reference.
I'm sure you all know the infamous "Man of Steel, Woman of Kleenex" theory that explains why Superman can't just fly around doing the dirty with regular folks, but if you need a reminder you can read the full theory yourself HERE.
I'll let the hilarious deleted scene above do the talking!