Hi, My Bro And Sis Inlaw Are Trying For Baby

Hi, my bro and sis inlaw are trying for baby since 4 rys but result are negative always, many treatments are done still negative... IVI, water bag cleaning, Laproscopy for blockages... and many more... both of there blood group is same as per hindu astrology the "NADI" should not be same to concive, but there "Nadi" is also same... dont now how they will get baby... pls suggest...