Assuming 53% of population are females that is 12.7 million with the condition. Using your 19/1000 that’s 241k babies a year under this subgroup. Maybe it is 1 in 50 million chance for those 241k babies a year? Still seems off though I did pull the 53% out of my butt but I vaguely remember there being a slightly higher % of females in the total population.
Assuming 53% of population are females that is 12.7 million with the condition. Using your 19/1000 that’s 241k babies a year under this subgroup. Maybe it is 1 in 50 million chance for those 241k babies a year? Still seems off though I did pull the 53% out of my butt but I vaguely remember there being a slightly higher % of females in the total population.