This is quite fascinating issue. There is also cultural aspect. For instance in China, one child policy created imbalance of genders. Parents prefer their singl

This is quite fascinating issue. There is also cultural aspect. For instance in China, one child policy created imbalance of genders. Parents prefer their single child to be a boy and with cheap USG they could pick and choose. Retirement time is also interesting. In Poland we used to have 65 years for men and 60 for women. Now its 67 for both (still in transition period so its increasing slowly to finally settle at 67).