A woman gives birth to a son. What is the probability that her second child will be a girl

It would be 50% because having a son won't effect the probability of the next gender of the offspring. Unlike having to pick out two variables out of a bag, being pregnant is like having a trail but once you become pregnant again the trail restarts and does not use the previous data. You become a girl if you have 2 x chromosome and a boy by having one of x and one y. the odds are 50/50