Scully is bang on with respect to whole blood and the placential barrier.
However, I DISAGREE with Scully's comments on fetuses sharing whole blood. Fetuses in monochorionic pregnancies do share whole blood because they have one placenta. The blood systems of both fetuses connect at the placenta either by artery to artery, vein to vein or artery to vein. In a large majority of these gestations (88 percent), the fetuses will develop WITHOUT Twin to Twin Transfusion (TTT) syndrome. However, in 12 percent of the these cases, a condition called twin to twin transfusion syndrome develops (where one fetus gets more blood from the other fetus). Some cases are mild while a lot of other cases can cause the death of one of the fetuses. Research has also noted that the MORE artery and vein connections between the two (or more) fetuses, TTT syndome is LESS likely to occur because there are different ways for the blood to offset from one fetus to the other.
Please also be aware that fetal nucleated red blood cells and of course white blood cells DO pass the placential barrier. In fact fetal nucleated red blood cells live more than 25 years in the maternal (mother's) blood.
I urge you to joy2bfree's url that he/she provided. In that thread I provide 2 urls to click on (I have also provided these urls below my name on this thread). One deals with an AJWRB article on the crossing of these cells and the second article deals with the natural transfer of whole blood between two individuals (fetuses). Also look at the other information provided by AJWRB.
While going at this, recall the Questions From Readers section in the Watchtower magazines of June 1, 1990 and June 15, 2000. The QFR for June 1, 1990 clearly reminds the readers that whole blood does not naturally transfer between individuals. The Watchtower also indicates that researchers have proved albumin crosses the barrier but red blood cells and other cellular elements of blood DO NOT cross the barrier. However, once you read the above scientific research, you find out red and white blood cells do naturally pass and the Watchtower's statements are NOT true. Also when it clicks in your head that fetuses are individuals (based on Watchtower doctrine) then monchorionic pregnancies show a way for one individual to naturally transfer whole blood to another proving the Watchtower's statements are false.
Think about this. A group that touts a Hospital Information Service that reviews more than 4,000 medical journals and has doctors on staff tells an outright lie about their doctrine. A doctrine that allows for the needless death of little children who need a life saving blood transfusion.
Whole blood transfer
Red Blood cell and White Blood cell transfer