Children are generally ruled by V house.
1st pregnancy is ruled by V house (to know if the baby is going to be male or female you should look at the sign on the cusp of V house) Male signs (Aries, Gemini, Leo, Libra, Sag, Aqua) mean boys;
Female signs (Taurus, Cancer, Virgo, Scorp, Cappy, Pisces) mean girls.
2nd pregnancy is ruled by VII house (if it is your second pregnancy then the baby's sex will depend upon the sign on VII house cusp)
3d pregnancy is ruled by IX house
4th pregnancy is ruled by XI house
5th pregnancy is ruled by I house
6th pregnancy is ruled by III house
and then you start with V house again.
I don't know if this house cusp sign thing works always but still seems interesting.