If only it were so simple. There are many reasons why more and more families have two working parents, but free trade is not a major contributor in and of itself. The single largest contributor to this phenomenon is the inflationary federal reserve system. Inflation and the easy money policies that drive its existence contribute substantially to the "consumerist" mindset. This mindset is characterized by a high time preference or an aversion to delayed gratification (1). This is also the driving force behind the meme of keeping up with the Joneses. Americans have purchased themselves into massive debt. The only way to pay off all of the debts in many American households is to have both parents working. Unfortunately, many naive parents provide their children with little or no understanding of fiscal responsibility, which will have the sad consequence of perpetuating this phenomenon.
1) This mindset and course of action is a reaction to the effects that inflation has on saving and purchasing.
1a) Inflation causes the realized returns on a particular monetary instrument for a saver to be less than the face value. In the best case where inflation is relatively stable and low, and there is a strong consensus that the future inflation outlook appears to be holding a steady course, the actual return is X% less than the instrument face value %Y, where X% is the inflation rate. Any additional uncertainty will force prospective savers to discount the instrument to some value of return less than the best case scenario. This reduces the incentive to save in an inflationary society.
1b_i) Inflation increases the incentive to spend now, when things are cheaper, rather than later when they will be more expensive
1b_ii) Inflation reduces the "cost" of borrowing money. Loans taken out during steady inflation are paid back with cheaper dollars as the date of the payments advances. Wages in societies with inflation increase with time and in response to the fall in the purchasing power of the unit of account, although not necessarily in a proportion which leaves the worker at the same level of purchasing power. General asset values tend to increase in magnitude when measured with a currency that is losing value.
1c) These factors have the effect of encouraging consumption now even to the point of borrowing, and have a discouraging effect on savings and thrift.
Anyway if this sounds intriguing check out mises.org for a coherent explanation of the deleterious effects of inflation.
Republic