Basics -
Barren signs are Aries, Gemini, Leo, Virgo,
Remaining 8 signs are either fruitful or semi-fruitful,.
Ascendant is health of native,
5th house indicates children
3rd house rules younger siblings
11th house rules elder siblings
Jupiter, moon give life

Rules for not having at least single child
1) Jupiter and/or moon are combusted or in debilitation sign or barren sign
2) Ascendant lord, 5th house lord are combusted or in debilitation sign or barren sign, and no planets in asc and 5th house
3) planets in asc and 5th house are combusted or in debilitation sign or barren sign
4) significators of 5th house signify maraka, badhaka houses from 5th house

Rules for not having at least single sibling
1) 3rd and 11th house lords are combusted or in debilitation sign or barren sign
2) planets in 3, 11 houses are combusted or in debilitation sign or barren sign
3) significators of 3, 11 th houses signify maraka, badhaka houses from 3, 11 th houses.

Author's Bio: 

Sri Tulasi is a professional astrologer and motivational speaker having more than 15 years of experience.