These authors have used the ALSPAC cohort to look at the range of normality and changing patterns in stools in the first four years of life.  Here.

You’ve got to admire a study which asks more than 12,000 parents about their child’s stools.  This gives us some valuable data on what is normal, and also some simple data on what is not normal - for example black stools are hardly seen at all at any age.  What I guess I might like to have seen, as a general paediatrician, is some data on:

• how many of the children had been breast fed, and whether their stools are qualitatively different - experience suggests yes, but this would be great to pin down
• how many of the children had been treated for constipation - which, one assumes, might tend to blunt the end of the distribution curve
• how many of the parents thought that the stool pattern was normal or abnormal - which is something I find that parents struggle with a lot
• whether medicines were changing the colour of the stools.  For example, we’re usually fairly comfortable that iron turns stools black - does it always?

If I know ALSPAC I’m sure that about half of this is already in their database, so come on then…