Just to add some context, the author also wrote a quantified self article about documenting every thing her daughter did [1] (time, food taken, diaper wetness, color of urine, thickness of poop, sleep habits, etc). These are not your standard parents.
To be fair, many 'new parent' classes urge people to record a good bit of that information, in the event that the child is having trouble gaining weight, has an illness, etc.
Mix that 'good advice' with the 'quantified self' band-wagon that rolled through and it doesn't seem too crazy for a journalist to have taken up that torch -- at least long enough for an article or three.
To have continued well after it became clear that their child was properly growing/healthy -- and other article subjects presented themselves -- would be something different though.
1: http://www.slate.com/articles/technology/data_mine_1/2013/07...