Forgive my ignorance.

[RedSidedSPR]

Can wanderings mate with ordinoide? Sirtalis species cant, maybe vagran is the same way?

[guidofatherof5]

Using the word "can't" when it comes to Thamnophis to Thamnophis possible breeding might not be the right word.

[RedSidedSPR]

From what I've read, it's impossible. The organs are so different, it just doesn't work.

[kibakiba]

Things can happen, it might be a one in a million chance, but it could.
Snakey will court with anything and he has even poked sticks with his hemipenes if Snap was slithering on them... It all depends on how hard the snake is going to try.

[Stefan-A]

From what I've read, it's impossible. The organs are so different, it just doesn't work.

Not impossible, just not as easy.

[RedSidedSPR]

I see.

[ConcinusMan]

Northwesterns are very unlikely to mate with other species. Your snake is 100% northwestern. No reason to believe otherwise.