Table 3:

Behavior mechanism tests - sorting into sunshine duration and mortality selection

Dependent variable	Father’s years of education	Mother’s years of education	Child being male
	(1)	(2)	(3)
A. number of days in the first 30 days of conception
the number of days in the first 30 days of conception:
0–2 h	−0.500 (1.349)	0.095 (0.884)	0.031 (0.053)
2–4 h	−0.878 (1.420)	−0.462 (0.860)	−0.017 (0.073)
4–6 h
6–8 h	0.377 (1.063)	−0.316 (0.821)	−0.011 (0.061)
8–10 h	−0.334 (1.087)	−0.616 (0.750)	0.002 (0.055)
≥10 h	0.972 (0.942)	0.013 (0.933)	−0.083 (0.056)
Number of observations	239,909	633,329	637,033
Adjusted-R²	0.423	0.310	0.012
B. number of days in the gestation period
the number of days in the gestation period:
0–2 h	−0.275 (1.699)	1.147 (0.715)	−0.024 (0.016)
2–4 h	−0.020 (1.368)	0.742 (0.662)	−0.049 (0.033)
4–6 h
6–8 h	0.239 (1.391)	0.723 (0.754)	−0.027 (0.021)
8–10 h	−0.264 (1.342)	0.026 (0.567)	−0.014 (0.022)
≥10 h	0.803 (1.093)	0.893 (0.609)	−0.019 (0.022)
Number of observations	239,909	633,329	637,033
Adjusted-R²	0.426	0.312	0.012

Source: China’s National Disease Surveillance Points system and China Meteorological Data Service Center.

Note: *, **, and *** indicate significance level at 10%, 5%, and 1%, respectively. Robust standard errors, clustered at the county level, are presented in parentheses. The dependent variables are father’s education years, mother’s education years and child being male. The left-out sunshine duration bin is 4–6 h. All regressions include birth year fixed effects and county-by-day of year fixed effects. Demographic controls include gender, birth order, maternal age and its square term, and dummies for mother’s education. Environmental controls include temperature bins (<-4°C, −4–0 °C, 0–24 °C, 24–28 °C, ≥28 °C), as well as mean precipitation, mean wind speed and mean relative humidity in polynomial forms.