does the father or mother contribute the blood to the fetus?
The fetal DNA in a mother's blood can already reveal an infant's sex and other traits inherited from the father. But picking out a fetus's entire genome from its mother's is much tougher, says Dennis Lo, a chemical pathologist at the Chinese University of Hong Kong, who led the study.
conflict between the mother and the fetus with respect to how much food the fetus should be given; the mother is equally related to the fetus and to any future offspring, while the fetus is not equally related to itself and any subsequent siblings.