No matter how great the talent or effort, some things just take time: you can't produce a baby in one month by getting nine women pregnant.

This is a genuine Warren Buffett line, and we can point to exactly where it comes from: his 1985 Chairman's Letter to Berkshire Hathaway shareholders, where he wrote, "No matter how great the talent or effort, some things just take time: you can't produce a baby in one month by getting nine women pregnant." He used it to explain the patience behind Berkshire's stake helping Capital Cities finance its $3.5 billion acquisition of ABC — an undertaking Buffett expected to be unexciting for a few years but worth the wait. The line was later anthologized in The Essays of Warren Buffett, which is why it circulates so widely in investing and management writing. It is worth noting that the pregnancy-and-scheduling analogy predates Buffett in different words — Fred Brooks made the same point in The Mythical Man-Month (1975) — but Brooks's phrasing is his own, and this particular sentence is documented, verbatim and in context, as Buffett's. The attribution is solid.