births

#!/usr/bin/python
### converges to 1 as the number of families goes up
families = 1000000
import random
m=1.0
f=1.0
for i in range(families):
    s=0
    while not s:
        if random.random()<0.5:
            m+=1
            s=1
        else:
            f+=1
print 'm:', m,' f:',f,' prop:',m/f