what are the effects of orchiopexy? is it ethical?

To make a male look normal?  In dogs, No IMO it is not ethical

Depends on the reason for doing it.  What context are you suggesting?  Cosmetic or health?
Dawn.

Procedures are only ethical if they convey some benefit to the patient. Orchioplexy is of no benefit to a dog, therefore IMO it is unethical.
:)

(I wanted to add to my previous post but was timed out for editing).

The major problem with the procedure in dogs is that it masks the condition, so the dog is then likely to be bred from. As it seems to have a strong hereditary content, this is of course inadviseable. Retained testicles in dogs should IMO simply be removed entirely, not surgically moved down into the scrotum.