While I was killing Driik villagers for loot, I noticed that the corpses of boys displayed 0 oz in weight. I switched my measuring system to metric and checked the weights again, which displayed as 5 grams. The girl children in contrast were within a normal weight range of 20+ kilos.
I made a new character to check whether the weight aberration happens with kids from other cultures. I spawned in the Koivula and found another boy who weighed 5 grams on death.
Since these are fresh killings, I don't have data regarding the resulting bone weights for male child corpses.
(Wow, this post is so macabre.)