They often burst at the seams after a few uses, although they are commonly given as gag gifts and therefore many may not be used at all.
Even the secretion of Bartholin's glans is imitated, by means of a "pneumatic tube" filled with oil.
The parts are sometimes vibrating and may be removable or interchangeable.
Some of the first sex dolls were invented by Dutch sailors in the seventeenth century who would be isolated at sea during long voyages.
By the 1970s, vinyl, latex and silicone had become the materials most frequently used in the manufacture of sex dolls; silicone in particular allowed a greater degree of realism.
A 1982 attempt to import a consignment of sex dolls into Britain had the unintended consequence of ending the law against importing "obscene or indecent" items that were not illegal to sell within the UK.