An aspect that I would not take into account is the expected impact of your children.
Most importantly, it just seems wrong to make personal-happiness decisions subservient to impact. But even if you did want to optimise impact through others, then betting on your children seems riskier and less effective than, for example, engaging with interested students. (And even if you wanted to optimise impact at all costs, then the key factors might not be your impact through others. But instead (i) your opportunity costs, (ii) second order effects, where having kids makes you more or less happy, and this changes the impact of your work, and (iii) negative second order effects that “sacrificing personal happiness because of impact” has on the perception of the community.)
An aspect that I would not take into account is the expected impact of your children.
Most importantly, it just seems wrong to make personal-happiness decisions subservient to impact.
But even if you did want to optimise impact through others, then betting on your children seems riskier and less effective than, for example, engaging with interested students. (And even if you wanted to optimise impact at all costs, then the key factors might not be your impact through others. But instead (i) your opportunity costs, (ii) second order effects, where having kids makes you more or less happy, and this changes the impact of your work, and (iii) negative second order effects that “sacrificing personal happiness because of impact” has on the perception of the community.)