I have two children. One is a girl who is full of grace because she was born on a Tuesday.
What do you think is the probability that my other child is a girl?
The probability of an unknown person being a certain sex is always very close to 50%, regardless of how many siblings they have of a one sex or the other (e.g. a couple that had 14 children who were all girls still has ~50% chance the next one will be another girl.)