Ho-ly shit... You got me thinking and - if it weren't so OP that it'd ruin the storytelling, the teleporters would make the federation the most terrifying army in the galaxy...

Transporters should be able to fix pretty much anything wrong with you. Lost a hand? Don't worry, we'll replicate it from your last transport. Feeling sick? Nope - we beamed the little beasties away. Just a little dirty? Uniform rumpled? That won't do, we'll just fix that for you. No need to stop what you're doing, it'll happen in the background, you won't even notice it's happening...

K'ovok, Klingon warrior, led his troop's third assault on the federation outpost. They had been locked in combat with the Federation army for three days now. His troops were covered in blood, mud and unidentifiable filth after three days of glorious battle.

The Federation "dolls" didn't even look sweaty. Their uniforms were clean, fit perfectly and they were still smiling - always smiling - with their white, perfect teeth.

K'ovok swung his bat'leth through the neck of a federation p'tagh and smiled with satisfaction as the body fell lifeless - and nearly headless - to the ground. He turned to find his next opponent...and heard the slightest hum. Whirling, K'ovok found himself facing the same man he had just beheaded shaking out his arms and smiling. Always smiling. Even his uniform was spotless.

"Nice swing" the Federation doll spoke, slowly adjusting his neck and jaw. "You sure can dish it out! Let's see if you can take it, too."

No plague, nor illness, nor infirmity ever touched the humans. As soon as they passed through one of their transporters, which was often, any deviance from perfect health was simply cleansed. From overeating to plagues to simple sloth, there was nothing the transporters could not repair, replace or remove.

Aboard a starship the systems were even more aggressive. So long as you wore your combadge, your vitals were measured for any abnormalities. A slight tingle on your skin as bacteria or just honest dirt was transported away, added to the biomass the replicators drew from. Occasionally, you might lose a few seconds of time in the case of a really bad mess. More than one officer could relate a story about dying of a heart attack of moment and then waking back up still in the command chair.

Of course, the transporter system had required generating an intensely thorough understanding of human biology to perform these feats. Most other species refused to make use of human transporters, for that very reason. The information required to configure them for "best effect" was simply too dangerous to hand to another species, however "benevolent" they may be. The Vulcans had famously accepted the "gift". And in fairness, the transporters did work as advertised. Disease, infirmities, even many indignities of aging simply went away from Vulcan, cured by the transporter.

But some still wondered, at what cost? The humans were allies, but they now had the data to engineer highly specific germs, plagues that could spread unseen through the galaxy, yet kill only Vulcans.

There was no evidence such pressures were being applied, but it was notable how quickly the aloof Vulcan empire had become fast friends with humanity. Subservient, even, to their so-called Federation of Planets.

Some whispered that it was yet more insidious - to function as they did, the transporters needed to understand your biology perfectly, from the beat of your heart, to the thoughts in your head. What if the transporters scanned for "unhealthy" thoughts and simply "cleansed" those too?

And yet The Federation came on, and ever on. Spotless and smiling.