I went down a bit of a rabbit hole this morning studying male reactions to becoming fathers, and I found this article that cites a study that states that males who have higher testosterone are more likely to become fathers, but after all males studied became fathers their T-levels dropped sharply though temporarily.
They study authors concluded that the drop is caused by the need to adjust: "having a newborn baby require many emotional, psychological and physical adjustments"...
TLDR:
The authors of the study are trying to form causal link where one doesn't exist to conclude that males who have children have lower T.
This gives the headline for journalists to write headlines like the original article: "Men's Testosterone Drops Steeply When Baby Arrives" and tradcon-adjacent sites to say things like "Raising human offspring is such an effort that it is cooperative by necessity, and our study shows that human fathers are biologically wired to help with the job."
