One such strategy is test-to-scale — close cousin of the venerable test-and-learn approach that’s long been a startup staple.

If your baby is "following the curve" of the growth chart ... and perfect like the lines of the chart. Kids bounce up and down the growth charts, depending on appetite, feeding issues, illnesses ...

"One mark on a growth curve means nothing," says Tampa ... "It used to be we could predict children would end up somewhere between their mom and dad (in height)," Evers says.