Question 343352
Look at the possible outcomes of the children in order of birth.
There are {{{2^4}}} or {{{16}}} total outcomes.
1.B	B	B	B
2.B	B	B	G
3.B	B	G	B
4.B	B	G	G
5.B	G	B	B
6.B	G	B	G
7.B	G	G	B
8.B	G	G	G
9.G	B	B	B
10.G	B	B	G
11.G	B	G	B
12.G	B	G	G
13.G	G	B	B
14.G	G	B	G
15.G	G	G	B
16.G	G	G	G
Look at the outcomes that have two boys and two girls.
There are 6 of them (4,6,7,10,11,13).
{{{P=6/16=3/8}}}