One of the more annoying aspects of secularism is the inability to effectively distinguish between whether we can do something and whether we should do something.
And to see the fact that something is scientifically or technically feasible as evidence that the moral law does not in fact exist at all.
Take this quote from the Punch today, commenting on the story about the Melbourne couple who aborted their IVF conceived twin boys because they only want a girl:
"Back to the Melbourne couple… if you object to the sex-selective abortion of their twin boys on faith grounds, do your beliefs not collide spectacularly with our clear and present ability to tamper so liberally – and so skillfully – with natural reproduction?
Do the very existence of IVF and gender-selection technologies not undermine central pillars of your religious conviction? If these practices go against the will of your god, why are they happening? Why were we built to reproduce in a way that can be simulated in a lab?"
Yeah well no my beliefs don't actually collide in any way with science's ability to manipulate nature.
So here is my take on what Catholics actually believe on this subject.
What Catholics actually believe...
God created us in his image, with free will and intellect. Christians do not believe that human beings are robots, constrained from discovering or doing things by some biologic equivalent of Asimov’s three laws of robotics.
In fact, he makes us able to make and manipulate nature and material things in turn, allowing us to participate in the work of creation with him.
Christians do, however, believe that God implants us with a sense of what is right and wrong, an instinctive awareness of what we call the ‘natural law’. And he does want us to make the right choices in accordance with it.
Unfortunately, as St Thomas pointed out, our sense of what is right and wrong is easily obscured by cultural constructs and perverted by our own desires. That is why God gives us the safety net of Revelation and the ongoing guidance of the Church to help us get it right.
So yes, human being could technically do all sorts of things that are forbidden by the natural law. They regularly do.
But that doesn’t mean they should. Because all of our choices have consequences, and as the same article points out, even at the purely material level, they have drastic impacts on individuals and societies.