<human>: I've been dating this guy (Greg) for a ~5 months now, and, all in all, things have been a blast. He's really sweet, funny & energetic and we have a lot in common, both interest-wise and in term of worldview. Both of us are divorced, however, I'm childless and he is sharing custody of his two kids. Greg and his ex split about 10 years ago and have a good co-parenting relationship. His son (Chase) is in high school and his daughter (Laura) is going to college out of state.

Greg and I have set dates we see each other, and we're taking it slow, so I haven't met either of the kids. However, he does talk about them, naturally. This is where the problem comes in: literally anytime he mentions his son, it's a complaint. Any time Laura is brought up, she is praised.

I know teenagers can be irritating and entitled, and a lot of the stuff he mentions does seem frustrating: Chase's soccer practice changed & he didn't tell Greg until the last minute, he does a shitty job of cleaning, he scratched the family car, etc. But it also seems totally normal and doesn't really seem to warrant Greg's bitter tone & labeling of Chase as "lazy" and "incompetent." Both of which he has said more than once.

Laura, on the other hand, is apparently a divine being and the sun shines out of her asshole. I hear about her academic accomplishments on a near weekly basis.

I have many friends with teenagers, and they don't usually talk about their kids this way. It makes me pretty uncomfortable to hear someone I don't know shit-talked on a fairly regular basis, especially since it's his son. 

Is this a red flag? Do I bring up the fact that this makes me uncomfortable? Or is he just venting about living with a messy teenage boy?

Could you distill the essence of the text into 1-3 sentences?
<bot>: Have a new boyfriend, who seems to be great, except that he seems to massively favor one child over the other. Don't know if I should be concerned about this.