If you have names for the parents, it is standard genealogical practice to enter them. However, to enter them in Wiki tree you need either a birth year, or a death year.
If Thomas Myhill is the only known child of these parents, an estimate for parent's birth could be 21 years before his birth year (explain in biography). If other children are known, it would be 21 years from the first known child's birth year.
Or you could put in an estimated death date for them, after 1667 - again, explain in the biography. Use {{DateGuess}} template as appropriate.
Someone else may know nothing about Thomas, but know something about another child of theirs, and would link up.
Hope this helps,
Margaret