I live in a location where hard liquor (48%-52% alcohol by volume) is frequently given to small children as young as two years old. This is usually not in large quantities, although a recent story in the local newspaper did report the death of a three-year-old by alcohol poisoning for consuming about 100ml in a short period of time. (This would be without water, as shots, and possibly on an empty stomach, per the local custom.)
Everyone knows that too much alcohol has averse effects, but I'd like to quantify this a bit if possible. Assume a healthy two-year-old child who weighs about 25 pounds; how much hard liquor would be unhealthy and why?
I'm looking for an answer that isn't zero for the sake of being zero (unless there's a true reason that any amount at all is damaging). Kids often taste it off the end of a chopstick or something similar, so dosages of <1ml in an evening may be realistic in the common case, a couple of times per month.
In other cases, a child will be able to drink from the glass, and once at a wedding I've seen a three-year-old nephew-in-law drunk as a result. His dad is undoubtedly giving him too much, but too much by how much?
This is the closest related answer I found on this site. The research cited suggests that even a short period of time with high exposure is damaging (which is obvious), but not really the minimum dosage for damage. Several sources posit that a little alcohol each day is healthy, suggesting a threshold effect is in place. Does the threshold also exist for children with developing brains, given alcohol quantities proportional to body weight and likely a coefficient related to mental development stage?
This is the closest related question I found on a web search. The Question was "If the quantity is small, is it still a risk?"; the Answer immediately sidesteps the question, asserts that 60ml is a small quantity, and then concludes by explaining that 60ml is not a small quantity.
The correct answer may be that the truth is intractable, similar to this fine answer, but the situation here is different. I'm not seeing multiple conflicting studies; rather, I'm seeing very little research on this topic. My guesstimate, based on absolute air, is that it's somewhere in the vicinity of 5ml, but I'm hoping there's some real relevant research out there given how important the issue and how absolutely prevalent of a practice it is.
Edit for clarification: For the purposes of this Question, I'm only interested in direct health effects and long-term damage, and not second-order effects like increasing propensity for alcoholism.
I'm really trying to understand how much physical machinery a two-year-old child has when it comes to processing alcohol, such that a few hours later they'd be just fine in the same way an adult is just fine after drinking a small amount of liquor.
Do the necessary enzymes exist at all in small children? If so, how much liquor would the child be able to process? (If not, what happened to the ~10ml that the child in my example consumed? What sort of damage did it cause?)