I don't understand the macroevolution argument.
Creationoids define species by inter-fertility: if they can mate, they're the same species.
They define macroevolution as creation of new species; that is, animals that can't mate with their parent's species.
They accept microevolution as a fact; genes can change over time.
So: why do they think
most genes on the DNA strand can change over time, but
some - the ones that control fertility - cannot? What mechanism selects those particular genes for perfect copy, while allowing others to be corrupted?
Do they think God put a plastic change-guard over that stretch of DNA, but not the rest?
I just don't get the mechanism by which they think this happens. At the DNA copying level, it's all genes. The copy machine doesn't know what its copying. How could it gaurantee fidelity for some pages and not others?
Maybe they think it's like the Holy Bible; if you sit down to copy a book, then you might make scribing errors; but if you sit down to copy the Book, then God will guide your pen and make sure it comes out perfect.
No wonder God never puts in a personal appearence - if he's personally watching over every transcription of a reproductive gene for every creature on Earth, he's going to be awfully busy.