All people of Mongol and Native American Stock are born with a mark that looks like a bruise on the lower back side . This is known as the "Mongol Spot" As we grow it gets faint until it disappears. This mark is what the old time Jibaros used to call "La mancha de Platano" it showed that you were native to that land. People of Native American descent tend to lose it with more and more mixing. So if your children have it you or their mother may have the Taino blood from more recent ancestors. Congrats.