Epstein continued: "Your degree is, I believe, an EdD, a doctor of education, earned at the University of Delaware".
"A wise man once said that no one should call himself 'Dr' unless he has delivered a child."
Biden's spokesman, Michael LaRosa, said that Epstein's article was "pretty gross", while Kate Bedingfield, Joe Biden's communications director, said it was "patronising, sexist, elitist drivel."
"Dr B earned a doctorate in education, so we call her Doctor," she tweeted.
"The title Mr Epstein has earned here is perhaps not fit for mixed company."
Northwestern University attempted to distance itself from Epstein's views, pointing out that he has not taught at the Chicago-based university since 2002.
They issued a statement saying the university "strongly disagrees with Mr Epstein's misogynistic views".
Many pointed out that men are rarely questioned about their use of the Dr honorific when they choose to use it.
Kamala Harris' husband Doug Emhoff also sprang to her defence and accused Epstein of sexism.
"Dr Biden earned her degrees through hard work and pure grit," he tweeted.
"She is an inspiration to me, to her students, and to Americans across this country. This story would never have been written about a man."
Meghan McCain, daughter of the late John McCain, also joined in with an outpouring of support for Biden on social media.
When Joe Biden is inaugurated in January, Jill Biden will become the first professor First Lady of the United States.
She'll also be the first First Lady to work outside the White House, carrying on in her career as an English professor at Northern Virginia Community College as well as dedicating herself to causes like cancer research, military families, and free community college.
