The greater cost is not having Mom available in the home on a daily basis.
There are exceptions, of course, but this is a cost not considered when
computing the bottom line. Years ago I worked with a very nice lady that had a
toddler and she stated that after she and her husband figured the true cost of
her work outside the home, just in terms of economics and nothing else, they
were only about $1,000 ahead per year by her working and she had a fairly
responsible position in a national firm. She said they wondered if it was worth
the social and emotional impacts to her children.