Parents' rhymes with:
parent's, parents, barents, parent's, parents, adherents, arrants, barents, celebrants, emigrants, entrants, grandparents, grandparents', hydrants, immigrant's, immigrants, immigrants', marantz, migrants, parent's, parents, registrants, torrents, tyrants, vagrants, warrants
Parents' sounds like:
paramedic, paramedics, paramount's, parent's, parentage, parentheses, parenthesis, parents, permeates, permits, permutates, pernod's, premadasa, prentice, prentiss, primates, printouts, prints, printz, promenades, promotes, pyramids