[MUSIC] Welcome to Understanding China, 1700 to 2000, a Data Analytic Approach, part two, section eight, Who Reproduces Prudence and Pressure. Who reproduces? Well, at some level the answer is relatively easy and straightforward. The sexually active. Married couples. And why do they reproduce? Again, the answer is largely straightforward. Either it's the unintended consequence of recreation, or it's the conscious decision of procreation. In other words, fertility and the level of fertility, fertility patterns, are highly sensitive to the question of whether or not there was a culture of conscious choice. Not just over mortality, but also over sexuality and fertility. In this week, we'll look at two measures of fertility. Total Fertility, which is the births to women age 15 to 49. And marital fertility which is the births to married women, over the number of married women age 15-49. And we'll look at these measures by age, and we'll look at these patterns to try to examine whether or not we can find evidence of a culture of conscious choice within marriage, or not. Now, this table summarizes all the available Chinese studies from the earliest period, when fertility can be estimated reliably. The total marital fertility rate, the TMFR, and the total fertility rate, the TFR are shown in the third and fourth column. The first column is the period under observation. The second is the location. The last column is the size of the study population. And what you can see is, is that on average, Chinese women married between the ages of say 20 and 50, regardless of the time period, regardless of the location, rarely had more than six children. Their European counterparts, had on average seven and a half, to nine children, that would be roughly 50% more children. And this low marital fertility is one of the most distinctive features, along with female infanticide, of Chinese historical population behavior. The figure contrast the age specific marital fertility, for six western European populations. From France, England, Scandinavia, Belgium, Germany and Switzerland. With five Chinese and one Japanese historical populations from Liaoning, from Jiangnan, from Taiwan, from Beijing, from a variety of Japanese populations and from Anhui. And you can see that before 1800, European marital fertility was much higher. Especially in the younger age groups, and declined more slowly. So, couples age 20 to 24. Had a marital fertility rate, for the East Asian populations of 200 to 300. While similarly married populations in Western Europe, had a martial fertility rate of 400 to 500, essentially double the East Asian rates. And this difference only began to gradually narrow, especially from say age 30 to 34, and finally came close to converging at age 40 to 44. Now, to some extent, such differences might be explained, by differences say in postpartum Amenorrhea because of the practice of breastfeeding. And so, what I show you in this chart, is the relationship of the duration of breastfeeding from 0 to 35 months, with a duration of Amenorrhea. That is, the period after birth, when the woman is still no longer susceptible to conception, because she has not yet begun to ovulate. And what you can see is that long breastfeeding, say as high as 3 years, could increase this period of Amenorrhea from less than half a year to almost 2 years. Now, Malthus believed that sexual behavior within marriage was generally uniform in most societies, and that any form of fertility control were rare, and unintentional consequences of poverty, and perhaps of this breastfeeding practices. In other words, the relationship between coitus and fertility should be roughly stable. And what you can see in this chart is graphed on the horizontal axis, so the number of coital acts per menstrual cycle, with the probability of becoming pregnant. So that you can see if you have eight acts, the probability of becoming pregnant is roughly 25 percent. Now, in China, these differences we saw in marital fertility, of almost 100%, suggests that while it may be true that part of the difference may be due to differences in breastfeeding, the remaining must be due to differences in coital frequency. So the implication is, that just as we saw, a calculus of conscious choice over the survivorship of children, especially female children. There was a similar calculus of conscious choice, over sexual behavior within marriage. [MUSIC]