That's correct. A neighbor comment mentions the shape of the uterus, but AFAIK this only matters in later stages of development (extrauterine pregnancies happe

That's correct. A neighbor comment mentions the shape of the uterus, but AFAIK this only matters in later stages of development (extrauterine pregnancies happen, and are quite deadly unless aborted since most tissues are not meant to be invaded by the placenta). Some of the non-electric signals are given by gradients of expression of the Homeobox genes. There is also a process of mutual differentiation where neighbouring tissues cause each other to differentiate. For example, holoprosencephaly happens when the brain fails to (fully) develop into two hemispheres. The most severe cases results in the formation of a single eye that in turn induces gross face deformity (Cyclopia, with a nose stub above the single eye). The mildest cases result mostly in normal people with a lack of smell and a single top central incisor. ---- https://en.wikipedia.org/wiki/Homeobox https://en.wikipedia.org/wiki/Homeobox https://en.wikipedia.org/wiki/Holoprosencephaly https://en.wikipedia.org/wiki/Holoprosencephaly