So does the Catholic doctrine see marriage as nothing more than a physical & religious agreement to procreate? Would the Catholic Church refuse to marry an impotent man because of his inability to procreate? Or a women that had her ovaries removed because of cancer?
Sex is fundamental to marriage. An impotent man is incapable of the marital act, so the Church cannot marry him. Infertility is not an impediment to the marital act, so infertile couples can still be validly married.
This article explains the difference in detail.
What if a couple is called to marriage simply because of their mutual love for each other?
If that calling includes sexual attraction to each other, and they're capable of the act, then they can be validly married.
Maybe they have a genetic predisposition to a horrible disease and do not want to put a child through that?
This assumes a utilitarian calculus that the Church finds abhorrent (disabled lives are not worth living, etc.) Human sexuality is primarily ordered toward procreation, and sex is fundamental to marriage. If a couple isn't prepared to consummate their marriage in a way that is open to the generation of new life, then they shouldn't get married.
What if two people who love each other with severe mental or physical disabilities, which would be detrimental to a child's upbringing, wanted to wed? Would that still be considered wrong?
Again, this is smuggling in assumptions about what sorts of lives are worth living. The orthodox Christian view of marriage has, for millenia, been conjugal and at least open to the possibility of new life. If you can't enthusiastically check both of those boxes, then you're not being called to marriage.
Why is a child the only thing that can force people to put needs of others over their own?
It's not and, coincidentally, marriage isn't the only option for those seeking companionship and support. I understand that most people are repulsed by the idea that some are simply unfit for marriage as deeply inegalitarian. But I think that says more about the impoverished modern concept of "love" than it does about flaws in Catholic doctrine.
No, i'm quite interested in those topics, and even if they differ with my worldview I am eager to learn more about the topic. Why is it that there is no room to evolve? To change philosophy based off of the world around us?
It has evolved, and continues to do so; but slowly and organically. Changes have to be logical outgrowths of what has come before. The modern concept of "marriage" is a radical break with orthodox Christianity. I don't see any way that a voidable legal arrangement for property rights can be reconciled with the Christian institution.
I guess that is a disconnect for me. How did people, who wrote the doctrine, know what would be moral in today's society? Morality in itself is something that evolves with conditions. Is it not?
They believed in the Revelation of Scripture, the existence of an objective moral law, and that human reason was capable of at least partially discerning that law.
William of Ockham challenged that last bit, which led to
nominalism undermining the second, and
empiricism robbing the first of its authority.
I didn't mean my previous comment about "incompatibility" to be dismissive, wooly. I try to approach this subject with epistemic humility. I'm usually arguing a minority position based on a metaphysics radically different from the majority. So I expect others to disagree with my first principles as much (or more) than a Buddhist or a Wiccan would.
How is that morally any different than a married couple who is prone to miscarriage?
Such a couple is conceiving through the natural marital act (rather than via a technician combining biological matter in a test tube), and they aren't creating fertilized embryos
en masse for a scatter shot attempt at pregnancy.
Would the church see their continued pursuit, despite multiple failures, morally reprehensible?
Not at all. Based on my understanding, the Church would commend them for taking their marital duties seriously, and probably suggest that they consider adopting if they continue experiencing difficulties with natural pregnancy.
What about a couple who pursues children despite their genetic predisposition to a deadly disease?
What's the issue? The Catholic Church is one of the few institutions left coherently arguing against the eugenic culling of disabled children
in utero.