The issue is market effects. If there is one company offering paternity leave, and one which doesn't, which one can offer cheaper prices? If both companies have

The issue is market effects. If there is one company offering paternity leave, and one which doesn't, which one can offer cheaper prices? If both companies have to offer paternity leave, they are both in the same situation. Still however, one employee becoming pregnant is often a big problem for very small companies, because the effect is highly discretized. If you have 5 employees, then a pregnant employee means 20% of your company's workforce is gone. So you really need social programs that pay instead of the employer during the time of the absence.