Not all baby dolls are made of silicone, but many of the more realistic models are, particularly those resembling newborn babies. Special types of firmer silicone are used for jointed dolls, but soft silicone gives a more realistic feel for cuddling.
Silicone is used to make baby dolls because of its texture. It also takes colors very well and can therefore be made to resemble skin relatively easily. This makes it most suitable for realistic dolls, and it is often used to make anatomically correct models rather than dolls for children to play with. However, dolls with cloth bodies and silicone limbs and heads are also often created for children's play.