> My brother is just a 6' and considerably smaller than I am.
That is already very large, please don't interpret this as a sign that your brother is less healthy than you. If you are considerably larger than 182cm, then by some measures you'd be viewed as being less healthy than your siblings because you're prone to all the problems large people have.
It is very likely you all three maxed out the size range available to you genetically and epigenetically by receiving adequate nourishment, as is common in industrial nations.
> Might there be a biological imperative to ensure that the first born is healthy
Probably not as such, but the psychological effect you're describing might create that impression: first-time parents obsess about everything because they don't want to make any mistakes. With subsequent children they realize they've been overthinking everything and they consciously apply what they learned the first time, instead of indiscriminately following through on every little thing that comes to their minds (like giving up soda).
It's also a very first-world way of thinking about children.
> Then with the later children parent lose the need to ensure their children are as healthy.
Again, I think you're postulating purpose where none exists, because you see a correlation between your "better" health and the amount of attention your mom applied to arbitrary details when she was carrying you to term.
Instead, evidence suggests that increased survival pressure in humans leads to an increase in the amount of children a couple has, and attention to individual children (including first born) goes down drastically.
My own anecdotal impressions of wealthy industrial societies imply that while first-time parents sweat arbitrary details, it's really the last child a couple has that receives special attention. Partly because the parents have better skills, but probably also because they know it's the last chance "to do everything right".
That is already very large, please don't interpret this as a sign that your brother is less healthy than you. If you are considerably larger than 182cm, then by some measures you'd be viewed as being less healthy than your siblings because you're prone to all the problems large people have.
It is very likely you all three maxed out the size range available to you genetically and epigenetically by receiving adequate nourishment, as is common in industrial nations.
> Might there be a biological imperative to ensure that the first born is healthy
Probably not as such, but the psychological effect you're describing might create that impression: first-time parents obsess about everything because they don't want to make any mistakes. With subsequent children they realize they've been overthinking everything and they consciously apply what they learned the first time, instead of indiscriminately following through on every little thing that comes to their minds (like giving up soda).
It's also a very first-world way of thinking about children.
> Then with the later children parent lose the need to ensure their children are as healthy.
Again, I think you're postulating purpose where none exists, because you see a correlation between your "better" health and the amount of attention your mom applied to arbitrary details when she was carrying you to term.
Instead, evidence suggests that increased survival pressure in humans leads to an increase in the amount of children a couple has, and attention to individual children (including first born) goes down drastically.
My own anecdotal impressions of wealthy industrial societies imply that while first-time parents sweat arbitrary details, it's really the last child a couple has that receives special attention. Partly because the parents have better skills, but probably also because they know it's the last chance "to do everything right".