127K views · 70 reactions | It’s not as simple as XX vs. XY....

12K views · 834 reactions | Part 13 #parents I know, know not all dads. And yes, the male determines XX vs XY chromosomes. | Caroline | Facebook

An “Intersex” whale? Nearly all mammals use the XX/XY chromosomal system of sex determination, where females carry two X chromosomes and males carry XY. (In contrast, birds use the ZW system, in which males have two of the same sex chromosomes.) Last fall, a fascinating study documented the first case of an XXY chromosomal aneuploidy in a southern right whale. Differences in chromosome number are called aneuploidies, and this particular whale has what’s known as Klinefelter’s. News reports, howe