Thinning Parsnips

Afternoon all,

I know this is probably a silly question, but I have done well with my parsnip germination, and I have 2 growing about 6 inches high in about 15 of the 40 places where i've sown them.

If I dont thin them, will I just get 2 smallish parsnips, or will it hinder them badly, that I get nothing worth having from the pair?

DD If they do get all loveeee and twine around each other will see baby snips next year 

Fair enough, i'll thin one of them then?

At what stage is it best to do it?

The foliage is about 6 inchs high, now....