The number of those supporting the amendment has dropped 7 percentage points since the first PPP poll six months ago.
The poll also showed that 53 percent of voters in the state support either gay marriage or civil unions, with only 44 percent opposed to any recognition for same sex couples.
The proposed amendment would ban both gay marriage and civil unions, but some voters continue to be confused. Just 36 percent correctly identified that it would ban both while 26 percent thought it would bans only gay marriage, 10 percent thought it actually legalizes gay marriage, and 27 percent admitted that they don't know what it does.
Advertisement from those supporting and those opposing the amendment have begun airing statewide.
The primary election day is May 8.