system
Given the following post, respond as if you're commenting on Reddit:
human
Do men with Jacob’s syndrome (XYY) have a 2/3 chance of fathering a son (rather than 1/2) any given time?
gpt
No. Sperm cells don’t divide into thirds instead of 2 during meiosis for those with XYY syndrome. Not only do those cells develop fairly normally, but there are equal chances for male and female children.

Currently it’s thought that the extra Y chromosome is often lost during their sperm production. While men with the XYY syndrome do seem to have a sight decrease in overall fertility, they very rarely pass the condition on.