Study says: "... we modeled PCE by administering THC (2 mg per kg, subcutaneously (s.c.) once daily) to rat dams during pregnancy (from gestational day (GD) 5 until GD20). This low THC dose does not recapitulate behavioral responses in the can-nabinoid tetrad assay or elicits cannabinoid tolerance after repeated administration, hence it represents a mild insult without any substantial direct impact on maternal behavior. ... In terms of human consumption, this dose is equivalent to THC content in mild cannabis cigarettes (joints) (5%), since the average THC content in illicit cannabis preparations has significantly increased in the last two decades (from ~4% to ~12%)."

The figure quoted is a concentration (5%), not a dose.

How much actual THC did the rats ingest? That's the question.

Fair enough, another commenter already gave 2mg/kg, but I should have quoted it too really. Edited with more detail.

2mg/kg subcutaneous. I don't know the conversion between subcutaneous and other forms of ingestion, but this would be equivalent of ~150mg of THC for an adult male. I also don't the THC content of weed, but it doesn't sound like an unfathomably high dose. I think the other design concerns are more likely to be the culprit here than external validity worries about dose.

Normal weed "flower" is 10-30% THC. So 1 gram of weed is 100-300ish mg of THC. A single prerolled joint is usually 1 gram of flower. So this dose is around 1 joint.

Edit: importantly this info is for smoked flower, edibles and concentrates are a little different because of how they are absorbed.

Smoking an entire 1g preroll by yourself is a huge dose for a human who doesn't have a high tolerance.

I mean, it would depend on the THC concentration, right? A 1g pre-roll with 30% THC would be 3 times as potent as the one with 10%, so I can totally see someone with rather low tolerance smoking a full 10-12% joint by themselves and feeling just fine.

There is a scaling factor between mouse and human dosage that I can't remember off the top of my head, but it's not 1:1.

Looks complicated. https://en.wikipedia.org/wiki/Allometry#Drug_dose_scaling

Whoops, yeah. I meant linear, not 1:1.

Just for reference, your average edible will come in a suggested dose of ~10mg THC per piece.