Baby Not Crawling? Reason Seems to Be Less Tummy Time. “(P)ediatricians …are noticing more and more
babies who are not lifting their heads when
they used to, who are not turning over and
who are not crawling at 6 to 8 months,
when popular baby books say they should.

Developmental specialists say they think they know why babies are acting this
way: it is an entirely benign, but unexpected and unintended, consequence of a
public health campaign to teach parents to put babies to sleep on their backs to
prevent sudden infant death syndrome.

An increasing number of babies never crawl at all, pediatricians say, going
directly from sitting to toddling. And they are seeing more parents … who are worried that something is wrong.” New York Times