Effect of ultrasound, sex composition of the first child, and their interactions on male probability (births 1975–92): linear probability model results from the second births
| Dependent variable: child is male | ||||||
|---|---|---|---|---|---|---|
| (1) | (2) | (3) | (4) | (5) | (6) | |
| First child is female | 0.036*** (0.006) | 0.035*** (0.006) | 0.036*** (0.006) | 0.036*** (0.006) | 0.037*** (0.006) | 0.038*** (0.006) |
| Ultrasound | −0.004 (0.005) | −0.009* (0.005) | −0.004 (0.006) | −0.015* (0.008) | −0.014* (0.008) | −0.010 (0.009) |
| First child is female × Ultrasound | 0.047*** (0.008) | 0.047*** (0.008) | 0.048*** (0.008) | 0.048*** (0.008) | 0.047*** (0.008) | 0.046*** (0.008) |
| Individual controls | No | Yes | Yes | Yes | Yes | Yes |
| County fixed effects | No | No | Yes | Yes | Yes | Yes |
| Year (of conception) fixed effects | No | No | No | Yes | Yes | Yes |
| Provincial controls | No | No | No | No | Yes | Yes |
| County-specific linear time trends | No | No | No | No | No | Yes |
| Observations | 86,356 | 86,356 | 86,356 | 86,356 | 85,016 | 85,016 |
| R-squared | 0.0042 | 0.0049 | 0.0108 | 0.0114 | 0.0115 | 0.0168 |
Note: Individual controls include mother’s ethnicity, education, maternal age at conception and its squared term, gestation length and indicators for the timing of initial prenatal care visits. County fixed effects are separate indicator variables for each county. Year fixed effects are indicators that allow for unrestricted differences in year-to-year changes. Reported in parentheses are standard errors clustered by county.
↵* denotes statistical significance at the 10 percent level, ** at the 5 percent level,
↵*** at the 1 percent level.