The tax calculation is impacted greatly by the income-splitting or (as in the case of the article) dependent spouse deduction regime. That can swing the full/pa

The tax calculation is impacted greatly by the income-splitting or (as in the case of the article) dependent spouse deduction regime. That can swing the full/part or full/full decision wildly in a particular direction, as appears to be the case in Japan. It's definitely tax policy as social engineering, depending on how much value a society places on children being reared primarily in the home vs. daycare. Are there any studies comparing outcomes? The other dimension of the full/part vs full/full configuration is elasticity in case person A has a crippling injury or is otherwise unable to work full time. If your lifestyle is set up with a need for maximal income, it's very difficult to take a large hit like losing one full time income. On the other hand, if there is the slack to allow person B to take on full-time employment and have person A do whatever (if anything) they are able on other fronts, then it may be possible to get the bills paid. It will likely be at the expense of a less ideal home life, but that beats the heck out of having mounting debt or being evicted due to financial obligations that cannot be filled. It's much like the engineering principle of designing a 25-50% material strength buffer into infrastructure where failure would have a large negative impact. I realize its an oversimplification in MANY ways, but this is more of an issue further down the income ladder. e.g. losing that 2nd income means that you can't pay rent or buy food, vs higher income couples where you might have to give up a vehicle or look at re-mortgaging the cottage on the lake. Those with higher aggregate incomes would also find it easier to have an emergency savings fund vs living paycheque to paycheque (I'm ignoring the question of whether full time employment in a career is a fundamental requirement for a fulfilling adult life)