The Role of the Y Chromosome in Penis Size

humans have 23 chromosomes and of these chromosomes one of them are the sex chromosomes. Some of the genes that play a role in penis size are actually found on the X chromosome so you do the math now on what is partially inherited from your mother. Another important little sub topic here I'm going to mention is X in activation and so you might see this at some point on the MCAT. It's another term you don't want to know and it just means tightly packed heterochromatin.