Woman Notices Mom Struggling with Crying Baby While Getting Her Nails Done. Then, She Steps in (Exclusive) Kayla Jo Singleterry is a single mom of two daughters, 8 and 6 months. By.

This piece is part of Scientific American’s column The Science of Parenting. For more, go here. It was 3 A.M., and my seven-month-old would not stay asleep.