The couple had one child, Napoleon Francis Joseph Charles.

FORBES: Connect

The couple had one child, a girl.

ECONOMIST: Jeanne Calment

One couple said their only child was taken away by mistake while they were working in another city.

BBC: Chinese babies 'confiscated for overseas adoption'

If a couple plans to have more than one child, the cost per sibling drops slightly, thanks to re-use of items like car seats and clothing.

FORBES: Magazine Article

As a rule of thumb, economists reckon that a family with one child needs 30% more income than a childless couple to maintain the same living standard.

ECONOMIST: Most of the rich world is short of babies

While more of these families might have access to health insurance after the implementation of the Affordable Care Act, right now, among same-sex couples raising biological, adopted or stepchildren, at least one parent or child does not have health insurance in 38% of same-sex couple families.

CNN: The real 'modern family' in America

Mr McFadden developed ways of modelling several types of choices, such as how many children to have. (He made time for three.) Multiple choices such as this one involve complex statistical analyses, since the factors influencing a couple to have their first child may not be the same as the ones that lead the parents of three children to have a fourth.

ECONOMIST: Economics focus