Genes are super weird to think about.
If you go back one generation you have two ancestors in that generation: Mom and Dad.
Go back four generations, and you have 16 ancestors that generation.
10 generations, 1024 ancestors in that generation alone.
100 generations, 1,267,650,600,228,230,000,000,000,000,000 ancestors that generation (that's 1.3 nonillion). And that's just going 100 generations back.
Obviously, there have never been remotely close to 1.3 nonillion humans born. Which means each ancestor of yours has tons of ancestors in common with your other ancestors. Every person's DNA is a combination of all the other contributors to their ethnic gene pools, just in slightly different amounts than other living individuals (e.g., if you're of French descent, your 10th generation French ancestor Claude Pierre Beaumont may have contributed 0.2% DNA to you, but 0.8% DNA to the next French-descent guy, and 0.5% to the next, only 0.1% to the next, and so on and so forth).
So beyond a few generations, reproduction is really about casting your genes back into the collective pot. Each one of your descendents 10 generations out is only very marginally you.
This is kind of sad, in that 'you' get diluted, mixed in together with everybody else as each generation goes on. But also kind of cool, in that all of humanity is really this big joint project, and you're a contributor.
It's very easy to make 'selfish' arguments about either state. You are selfish to have children, because you are creating more like you and driving more resources to more mini-yous. Conversely, you are selfish to not have children, to live a life more based on personal hedonic gratification and not do your share contributing to the human gene pool. The "it's selfish" argument doesn't hold much water, since it's equally applicable to either choice (and people can debate about this - usually in the form of "my decision isn't selfish; YOUR decision is selfish!" - but the point is the argument lends itself easily to whatever decision you want, which makes it better as a tool for justifying the choice you make than for making that choice to begin with).
'Guaranteeing control' is impossible, of course. You can't guarantee control over any other organism... kid, girlfriend, wife, parent, dog. Even if you lock them in a room and tightly monitor all access they have to the outside world, you still can't stop them from thinking thoughts you might not have planned for them. A big part of life is realizing the limits of your ability to control the world and people around you.
Anyway... if enough people with similar genomes to you fail to reproduce, then yeah, your genes get weeded out. Or if people with genomes similar to you reproduce less than people with different genomes, your genome becomes comparatively rarer as those like you are gradually genetically outcompeted.
There are plenty of roles in society for non-reproductive human beings. Every individual plays a part; economic contributions, artistic contributions, contributions toward pushing society this way or that way purely by communication, championing ideas, etc. None of Leonardo Da Vinci, Isaac Newton, or Nikola Tesla passed on their genes. But we keep getting Da Vincis, Newtons, and Teslas because all the genes that made them up are still there in the gene pool, and sometimes enough of those genes come together to produce another one like them.
You will have to decide for yourself what the 'purpose' of being alive for you is. We don't have a singular religion/ideology in the West right now telling us all what our one shared purpose is. So instead it's more a chaotic smorgasbord of various people with various purposes (and many people with no purpose).
Reproduction is one possible purpose. It's not the only, nor is it a universal, purpose. Most people choose to reproduce; some do not.
More discussion on purpose and reproduction here, if you haven't read it or it's been a while:
The Purpose of Life from a Practical Point of View
Hope this didn't make things even more confusing. Just trying to add some perspective I don't usually see discussed in the "to reproduce or not to reproduce?" discussions.
Also, it may not be worth worrying too much about "Should I or shouldn't I reproduce?" From everything I've been able to tell, it's much more deep-seated/unconscious decision making and much less prefrontal cortex calculating. Either you like knocking chicks up or you want a mini-me running around, or the thought of swollen female bellies and small versions of yourself horrifies you. It's much more emotional than rational, this baby-making business.
Chase
