No, the problem comes when the father and mother have different RH factors.   The baby has to have the same RH factor as the father.  If it is born with the mothers RH factor and it is different than the fathers then they must do an emergency blood transfusion.

The top are the Brazilian wandering spider aka Banana Spider, the Australian funnel web, the Brown recluse aka Fiddle back, the black widow aka red back, Mouse spiders, the six-eyed sand spider, and the sac spider. The rest of the list are varieties of tarantula's, Huntsman spiders, the wolf spider, and Hobo spiders although they … Read more

That depends on where you live.  In Dallas we fill our 500 gallon tank once a year.  It is used for hot water and heating but a friend of mine who lives close to Chicago fills his 1000 gallon tank 2 to 3 times a year.