Probably a stupid question but these spots are appearing over my shower right at the line where the wall meets the ceiling, basically. They are in the area directly above the shower but also extend a couple feet to the right beyond the shower.

My wife thought they indicated a roof leak but based off Google, it looks like this may be mold from poor ventilation? I know my wife and daughters can take some LONG steamy showers.

How old is the house? I thought it was a code requirement to have a bath exhaust fan in any bathroom without a window. Cant help with mold but it's possible that it is. My house is crazy old so there are not vents or windows. We do have ceiling fans in on and I just run that any time the shower isn't being used and there are no mold issue.

But either way, if it's mold, I wouldn't fret. Squirt it with Concrobium. Call it a day.

It does not have a roof leak appearance in my opinion from the pics.

We run a dehumidifier in the bathroom 75% of the year for a few hours after showers due to how humid it is in Houston.

Might be something to consider if it is a mold issue.

Built in 2004. Window in the bathroom doesn't open but there is an exhaust fan. It's a large bathroom though so not sure how effective it is. I'll get some of the mold killing spray. Appreciate it!

Get some concrobium and clean it.

Had something similar. Kids never bothered to tell me until the plaster started cracking and falling off.

Turns out there was a vent on the roof. Vent has a flapper to keep rain from going down it. Flapper was broken. So only in rain where it was an absolute downpour was rain going down the vent, down a 2x6, and to the bathroom ceiling (not directly below said vent).

My roofer buddy came over, got on the roof with a water hose, and soaked the vent while I got up in the attic and watched. Took several minutes but the water finally started coming through.

Easy / cheap fix. Hopefully yours is as well.