Father makes statement that has me worried

Please Help! (I didnt know where to post this) When my child was a newborn his father made the comment "You have a big penis like daddy" while I was changing him. We are no longer together due to many reasons. I get it could have be an "immature" thing to say however sexualizing your child and comparing penis to sizes it's not okay to me and it's bothered me for months... I've never asked him to change his diaper not that he's asked because one I don't think he's capable of doing so correctly and he's not around much but this comment made me worry... Am I over reacting or is this a red flag? ( please no hateful comments, I'm just a concerned mother )