Wanderlust World Wanderlust World The natural human sex ratio at birth is ~105 males per 100 females (approx. 51.2% boys). This holds for North America (U.S., Canada, Mexico) as well.
The statement "slightly more girls" is incorrect. The slight male excess at birth is a biological constant across populations. However, because males have higher mortality at every age, the ratio equalizes by reproductive age and reverses in older cohorts—women outnumber men in the total population (especially 65+).
Current US sex ratio at birth: 1.048 (104.8 boys per 100 girls). Canada: 1.055. Mexico: 1.050. The bias is small but consistent.