The probability of a boy is still 0.5 no matter how many prior children there are.
50/50
It depends on the couples' genes. Also, at present the probability of a girls is approx 0.48
3 out of 7
Since the probability of having a son is about 1/2, the probability of the first 4 children being boys is about (1/2)4.
Assuming the chances of having a boy and having a girl are equal (50/50), there are 4 possible outcomes from having 2 children. BOY-BOY, or GIRL-GIRL, or BOY-GIRL, or GIRL-BOY. Since each outcome is of equal probability it means there's a 25% chance the first will be a girl and the second will be a boy.
The probability of having a girl versus a boy is 1/2 because there is two things you have a chance of getting and you can only get one or the other.
The probability of a boy is still 0.5 no matter how many prior children there are.
50/50
It depends on the couples' genes. Also, at present the probability of a girls is approx 0.48
These events are independent; so the probability of a girl is 0.5.
1/8?
It is always 50/50.
3 out of 7
Since the probability of having a son is about 1/2, the probability of the first 4 children being boys is about (1/2)4.
If we consider there is a 50% chance for having a boy and 50% for having a girl*, there is : - 12,5% chance of having no boys; - 37,5% chance of having 1 boy; - 37,5% chance of having 2 boys; - 12,5% chance of having 3 boys. Therefore, there is 50% chance of having at least two boys. *The odds are more like 51% for having a boy and 49% for having a girl, but it doesn't really matters.
Assuming that the probability of having a baby girl is 1/2 and that of having a baby boy is 1/2, the probability of having 3 baby girls in a row is (1/2)(1/2)(1/2)=1/8.