Initially expensive, the cost of silicone dildos has dropped over time. Silicone rubber dildos became popular in the 1990s. Manufacturers recommend using condoms with these toys if users share them. Products made of PVC or thermoplastic elastomer ('jelly rubber') cannot be sterilized. Phthalates are linked to health problems such as cancer and prenatal defects. PVC and jelly-rubber toys are problematic because they contain unsafe phthalates, softeners added to many plastics that are also found in some jewelry, food containers, and other soft rubber toys. Most of the inexpensive dildos sold in the 2000s are made this way. Later, PVC dildos with a softer PVC filler became popular. This arrangement was unsatisfactory because of the potential for injury from cuts by the spring if the rubber cracked and came apart. Rubber dildos, usually incorporating a steel spring for stiffness, became available in the 1940s.
