"I have never been to New York, and my son has never been to New York either."
'Either' becomes 'neither', and the subject and verb are inverted because of the negative:
"I have never been to New York, and NEITHER HAS MY SON (ever been to New York)."
The part in brackets is perfectly OK, but would normally be used only for emphasis.
Compare the sentence with this one, which has the same meaning:
"Neither my son nor I have ever been to New York."
- For Teachers