What is the effect if you have an extra female chromosome?

Usually none. 62% of 47, xxx women are reportedly physically normal. They have a tendency to be tall, with many reaching the 80%tile by adolescence. Puberty and fertility are within the normal range. Their verbal and performance iqs are 15 to 20 points lower than those of their siblings. These women do not appear to be at increased risk of having chromosomally abnormal offspring.