If you could make your mother sinless...

One Catholic "argument" Mike Winger mentions in his demolition of Marian typology is: "If you could make your mother sinless, wouldn't you?"

Winger doesn't respond to that directly, in part because his focus is exegetical, and because he thinks that's bad theological method. I agree, but it's still good to address it head-on:

1. Ironically, it's a proof for the Immaculate Conception which, if sound, disproves the Immaculate Conception. If the Immaculate Conception is true, then Jesus wasn't the agent of the Immaculate Conception. For one thing, Jesus didn't exist prior to his own conception. Jesus is a product of the Incarnation. 

Of course, the Son is eternally preexistent, so that in principle, the Son could be the agent of the Immaculate Conception, but the Catholic prooftexts single out the Holy Spirit as the agent of the Immaculate Conception. So the argument, even on its own grounds, is self-refuting. 

2. Then there's the argument from analogy: 

i) How could a human son makes his mother sinless before he was conceived?

ii) As a preliminary step, a Catholic apologist would have to demonstrate that retrocausation is possible. That's a very tall order.  

iii) But even if (ex hypothesi), he could retroactively make his mother sinless, at her own conception, yet in that event he wouldn't exist in the first place since his mother would have a different future if she was sinless from the moment of conception. He wouldn't exist in that future. He only exists in the future where his mother isn't sinless. So the attempted parallel, using merely human sons and mothers as a basis of comparison, is incoherent on yet another ground. It's like the Grandfather paradox. If the time-traveler succeeds, he erases the future he came from. So he never existed! 

iv) In Catholic theology, Jesus and Mary are both sinless. Yet in the comparison with merely human mothers and sons, the mother would be sinless but the son would not be. That, however, would be a very strange mother/son relationship. How exactly is that supposed to work?

v) Everyone who dies in the faith will be sinless. So what's the hurry? I don't need to make my mother sinless. That will happen in due time. There's a reason why God doesn't make humans sinless in this life. Faith is waiting.