Assuming a regular, healthy father, the odds are almost exactly 50/50 for each pregnancy. So 0.50x0.50x0.50x0.50x0.50x0.50=0.015625, or about 1.6%. One way to think about that number is if you had 1000 families of 6 children, 16 of them would have all six girls. The important thing to remember is that each pregnancy had a 50/50 chance, and the fact that you had 5 girls before does NOT make a boy more likely for the 6th pregnancy.
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Assuming a regular, healthy father, the odds are almost exactly 50/50 for each pregnancy. So 0.50x0.50x0.50x0.50x0.50x0.50=0.015625, or about 1.6%. One way to think about that number is if you had 1000 families of 6 children, 16 of them would have all six girls. The important thing to remember is that each pregnancy had a 50/50 chance, and the fact that you had 5 girls before does NOT make a boy more likely for the 6th pregnancy.