Blood groups

[raywootten]

Do children usually have the same blood groups as their parents?

[moorby]

Generally yes BUT the situation is complicated in that a parent with group A or group B blood can carry group O genes 'hidden' by the A or B - so though there are combinations that are impossible. You have to sit down with some paper and work out all the possible genetic patterns to work out which A group AB parent could pass on A or B genes

[moorby]

Of course there are even more complications in that as well as the ABO blood group there are 400+ other blood groups you could test. If you are really interested in paternity the easiest way is to get some DNA fingerprinting done

[Ginbottle]

Children would have a different blood group from their mother or else the first-born would be a rhesus baby.