Harvard historian Niall Ferguson posted an "unqualified apology" on his personal blog on Saturday after saying that British economist John Maynard Keynes did not care about the future because he was gay and had no children.
The comments were "as stupid as they were insensitive," Ferguson wrote.
While speaking at a conference of investors in California on Thursday, Ferguson was asked to comment on Keynes' observation that "in the long run, we are all dead." He described his response as "off the cuff," and not part of his formal presentation.
His comments were first reported in Financial Advisor magazine, which wrote that Ferguson described Keynes as an "effete" member of society who was more likely to discuss poetry with his wife than procreate.
The magazine did not quote his full remarks directly.
Keynes was an influential 20th-century economist who championed government's role in helping manage the economy.
"I should not have suggested - in an off-the-cuff response that was not part of my presentation - that Keynes was indifferent to the long run because he had no children, nor that he had no children because he was gay," Ferguson wrote on his blog. "This was doubly stupid."
"First, it is obvious that people who do not have children also care about future generations. Second, I had forgotten that Keynes's wife Lydia miscarried," he wrote in the blog, titled "An Unqualified Apology."
The Scottish-born Ferguson, who has written critically acclaimed books on the history of finance and also writes for the Daily Beast website, added that his disagreements with Keynes' economic philosophy "have never had anything to do with his sexual orientation."