Love isn't easy. Being in a relationship requires a lot. Imagine if you're a super-hero trying to maintain a relationship. There are many responsibilities a hero faces. Their time is divided between their normal life and heroic duties. If a hero manages to find love with another superpowered individual, that could solve some of the problems. The fact that both are super-heroes allows for more time to be spent together.
In the 30th Century, you would think things would be easier. With the advancement of civilization and technology, there shouldn't be anything separated two lovers. Brainiac 5, in the Legion of Super-Heroes is a genius and should be able to overcome any obstacle. It was in 1974's Superboy #204, we see the love troubles facing Brainiac 5.
Brainiac 5 was the most level-headed member of the Legion of Super-Heroes. In the story, "Brainiac 5's Secret Weakness," we find out not only is he suffering from a nights of restless sleep, he is also head over heals in love with Supergirl. She might not have been with the team for long but she was the only girl he ever loved. To make things worse, he never found how she truly felt about him. Separated by ten centuries, would could a young genius in the future do to solve his love troubles?== TEASER ==
Brainiac 5 doesn't have to mope in sorrow for too long. Almost as if his wishes came true, Supergirl turns up in order to be with him. She wasn't there to serve in the Legion, she was there to be with Brainiac 5.
Determined to sort out his priorities, Brainiac 5 soon announces he is quitting the team and leaving with Supergirl. As they fly away in a spacecraft, their happiness may soon be short lived. The ship's sensors pick up a deadly Zotron belt of radiation in their path. We can only assume there's no way to avoid this radiation. Because the rays are so concentrated, they will filter through the ship and vaporize them into nothing.
Apparently Supergirl's cape must have been made of Kryptonian material. Whipping it off, she covers and seals Brainiac 5 before the rays can hit. When he's able to remove the cape, he sees Supergirl standing there but she tells him she just got there after Star Boy called her to help (if she was in the 20th Century, imagine the long distance phone bill). She quickly points (most likely creeped out) to a robot lying on the floor.
Brainiac 5 was shocked to discover that the Supergirl he was running off with was a mechanical android. Where did she come from? That's where the lesson part begins. It turned out Brainiac 5 secretly built her during the nights. So secretly, he wasn't even aware. This is why he was so tired. He was sleep-building.
Essentially what Brainiac 5 did was build a girlfriend. His heart ached for the only girl he ever really loved. Instead of sitting around moping all the time, his subconscious took over and built an android to resemble Supergirl (and also have her super-powers). This is something that couldn't easily be done in today's time. Even if you were a...brainiac, the technology wouldn't be there to build a robot so life like, it would fool even yourself.
What's even more strange about all this is Supergirl's calm reaction. She had been away from the 30th Century and the Legion for who knows how long (sure we could check the previous issues but that's not the point). She swoops in to save Brainiac 5 and finds out he ran off with an android built to look exactly like her.
For Brainiac 5, getting a girlfriend was just a matter of building a robot and programing it to love him. With the ease of time travel, you would think it'd be easier to simply travel back to Supergirl's time and find out if she had any feelings for him or if she thought he was a dork. In the future, it's apparently just easier to build one...in your sleep.
It's not surprising that they called this "Brainiac 5's Secret Weakness." If you think about it, this whole thing is pretty dang creepy. He was making out with a mechanical facsimile of Supergirl. If they hadn't flown through the deadly Zotron belt of radiation (which must be impossible to avoid or fly around), how long would Brainiac 5 and his robot stayed together. For that matter, where were they even going? Would Brainiac 5 have lived happily ever after? Would a...situation come up where he would discover he was with a robot. It's a scary thought.
Building a girlfriend might be acceptable in the 30th Century but you don't need to have a significant other to define your life. Brainiac 5 should have picked up a hobby or something. From now on, he's always going to be that creepy green dude from the future in my eyes.