If Tom Harris had type AB blood and Mary had type O, could the type O child they brought home be their child? * No, the baby would have to have inherited a gene for O from both parents and Tom has only a gene for A or B. Yes, both parents had the recessive hidden gene for O blood in their genotype which they passed on to the baby. No; the baby would have to have Type AB blood that it inherited from the father since A and B are dominate to O. Yes; the baby inherited type O blood from the mother Mary Harris which is dominant to the genes for both A and B.