Preliminary research has found that papaya seeds have contraceptive effects in male monkeys and potentially humans. Unripe papaya is more effective than ripe papaya at suppressing progesterone and could induce miscarriage in large amounts, though ripe papaya is generally not teratogenic in small amounts. Papaya may also have anti-cancer and antibacterial properties. The papaya industry in Hawaii was nearly wiped out by disease in the 1990s but has since rebounded through the use of genetically modified varieties.