Question 1108679
Here are all the possible outcomes for having 4 children, sons(S) and daughters(D):
<pre>
SSSS+       DSSS+
SSSD+       DSSD*+           
SSDS+       DSDS*+
SSDD*+      DSDD
SDSS+       DDSS*+
SDSD*+      DDSD
SDDS*+      DDDS
SDDD        DDDD
</pre>

The starred * items show which entries have exactly two daughters
The entries with + indicate cases where they have two or more sons

Hence the intersection is the 6 entries with *+