His Senate and campaign biographies say he is married with four children but do not make clear three are his stepchildren

He married a college sweetheart and they lived in a sugar shack on 85 acres of land, without electricity, but divorced after 18 months

Democratic presidential candidate has said nothing about his family life in the 1960s when he was living in Vermont as a 'revolutionary'

Bernie Sanders' bid for the White House was placed under a shadow Thursday as new questions arose as to why the self-described Democratic Socialist has kept his complicated early love life secret for so long.

Sanders has never discussed his first marriage nor the fact that his only natural-born child was with a second woman.

But Daily Mail Online has pieced together the fragments of his life as a revolutionary living in his adopted state of Vermont.

And they reveal that he was married to one woman, yet had his son Levi with a second - long before he went on to marry his current wife.

The Sanders campaign did not respond to Daily Mail Online's queries about why the veteran senator has kept details of his early life so quiet nor how he expected them to remain secret during his run for the nation's highest office.

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Future first lady? Bernie Sanders and his wife Jane O'Meara Sanders as he was about to give the speech officially announcing his candidacy for the White House

First wife: Deborah Messing, born Shiling, was Bernie Sanders' college sweetheart and they moved to Vermont but they divorced 18 months after marrying

Mother of his child: Susan Mott Glaeser, with whom Sanders had his son, Levi, in 1969

The Sugar Shack: Sanders and his first wife Deborah Shiling paid $2,500 for the property on 85 acres of land just outside the small hamlet of Middlesex. It had no electricity, but Deborah told Daily Mail Online there was water - 'too much' of it

His campaign website says that he 'lives in Burlington, Vermont with his wife Jane. He has four children and seven grandchildren'.

Sanders is making a long-shot bid to upset Hillary Clinton as the Democratic candidate in next year's presidential election.

If he were to be successful and beat the Republican candidate in November 2016, he would become only the second divorced president in history.

But unlike Ronald Reagan, whose first wife, Jane Wyman was an Oscar-winning actress who was still playing a leading role on television's Falcon Crest at age 72, Sanders' first wife, Deborah, lives a quiet life.

For 20 years she worked as a buyer for the Hunger Mountain Coop, a '20,000 square foot community-owned natural foods cooperative' in Vermont's capital, Montpelier.

Daily Mail Online has learned that Sanders married Deborah Shiling, who is three years his junior, on September 6, 1964.

Her father was Dr. Moses Shiling, at the time chief of pulmonary diseases at Sinai Hospital in Baltimore. The ceremony was in the garden of her parents' home in Baltimore.

Deborah, now remarried and known by her married name of Deborah Messing, confirmed to Daily Mail Online that she had been briefly married to the 73-year-old presidential candidate.

Activist: At the University of Chicago, where Sanders studied, he began his career which would lead to the run for the presidency. He was photographed at a racial equality sit-in in January 1962

Son: Levi Sanders, 46, is following in his father's liberal footsteps, posing with Barack Obama, then a senator, before he became president

Family: Levi Sanders (left) was among those on stage with Bernie Sanders as he announced his run for the presidency

Family: His campaign has also published this picture of the Sanders family. On his campaign and official website Sanders says that he is married with four children. In fact three are his wife's, who he treats as his own, while his son Levi is by another relationship

1974: The father of a five-year-old son, Sanders campaigned for the senate as an independent

'I really don't want to say much,' she said. 'All I can say is I believe in Bernie Sanders and I am a strong supporter.'

The couple met in college and moved to a sugar shack without electricity on 85 acres of land in Middlesex, a small hamlet just outside the Vermont capital of Montpelier. They bought it for just $2,500.

But the marriage did not last, and Bernie and Deborah divorced in 1966 after 18 months. Soon afterwards Deborah married her current husband Bob, who she describes as 'a poet slash logger slash philosopher'.

They now live in a house on a steep hill less than a mile from the gold-domed statehouse that dominates Montpelier.

Sanders, now 73, went on to live with Susan Mott, and together they had a son, Levi, now 46. He was born in Brightlook Hospital, St. Johnsbury, Vermont on March 21, 1969, publicly available records show.

Daily Mail Online has been unable to find any record of Sanders marrying Mott.

Mott is now married to German immigrant Hendrik Glaeser, who has run a sign-making business in Burlington, Vermont's largest city, for some 30 years.

Their wedding certificate records her name as Susan Mott.

When approached by Daily Mail Online at her Burlington home, she said: 'I really don't want to do this.'

Asked whether she thought that Sanders could have kept his secrets as he ran for the nation's highest office, she smiled, saying: 'I am not a chatty person'.

Sanders eventually married Jane O'Meara in a civil ceremony in Burlington of May 28, 1988. They are still married and Sanders treats her three children, Heather, Carina and David as his own.

All reports about Sanders have previously said that Levi was the result of Sanders' first marriage, although the name of his first wife has never before been revealed.

In its biography, CNN says his first wife's name is 'unavailable publicly' and lists Levi as a child of that marriage.

Business: Susan Mott, the mother of Bernie Sanders' son Levi, is now married to German-born Hendrik Glaeser, who runs this family business in Vermont

Still an ally: Messing, who was Bernie Sanders' first wife, is still a supporter and says he is a 'friend'

Packing them in: Sanders is filling large-capacity venues as he surfs an unexpected wave of support

History: Ronald Reagan was the first divorced president, with his second wife Nancy as first lady.

His Wikipedia page says: 'First wife (name and dates unknown).'

His official biography on the Senate website doesn't even mention a first wife at all and lists his children as Levi, Heather, Carina and David without differentiating between children and step-children.

Even people who have researched his life know little about the threads of his love life. In his book 'The Jews of Capitol Hill', Kurt F. Stone wrote: 'Sanders, his first wife and their son Levi, lived without electricity or running water in a converted sugar house,' when they first moved to Vermont.

However Deborah Messing told Daily Mail Online Levi was not born at that time — and the house had water. 'In fact we had too much water,' she said without elaborating.

Sanders has previously been reported to have styled himself a 'revolutionary' when he moved to Vermont.

The New York Times reported last week that he had written an article in an alternative newspaper headlined 'The Revolution Is Live Versus Death'.

Sanders told Chris Cuomo on CNN on Friday that he accepted that his personal life is going to be up for play in the election.

'I'm not being naive,' he said, 'I don't think I can avoid it.'