We cannot say how much of the difference is the result of selectivity of migrants at the time of move and how much results from lowered fertility after moving to the urban setting.
我们无法说这个差距在多大程度上取决于移民时的选择，多大程度上取决于移民城市后生育力的下降。
2
And the difference was clear, with fertility declining by up to seven per cent with each extra year on a man's age between 41 and 45.
区别很明显，处于41岁到45岁之间的男人，每长一岁，生育能力下降的最大幅度为7%。
3
Apart from coercion, the big difference between fertility in China and Thailand is China \ \; s gender imbalance.