But I also would distinguish between secularization (and other kinds of modernization) and Westernization. (Japan did the one but not the other, for example.)
Where your argument is concerned, it’s a distinction without a difference. Secularization absolutely destroys birthrates. When Japan secularized, its total fertility rate (TFR) dropped to 1.4. China’s TFR was 6.32. It is 1.6 today. India’s TFR has dropped from 5.9 to 2.2. The decline in the Arab world, while not as severe as that in Asia, is still pronounced. Egypt’s TFR has dropped from 6.7 to 3.3. Jordan dropped from 8.0 (!) to 2.8. Morocco dropped from 7.0 to 2.4.
I think secularization is a nontrivial cause of these declines.
Where your argument is concerned, it’s a distinction without a difference. Secularization absolutely destroys birthrates. When Japan secularized, its total fertility rate (TFR) dropped to 1.4. China’s TFR was 6.32. It is 1.6 today. India’s TFR has dropped from 5.9 to 2.2. The decline in the Arab world, while not as severe as that in Asia, is still pronounced. Egypt’s TFR has dropped from 6.7 to 3.3. Jordan dropped from 8.0 (!) to 2.8. Morocco dropped from 7.0 to 2.4.
I think secularization is a nontrivial cause of these declines.