Lombardi said she shares the same closeness with her 26-year-old daughter and her son is close to his father.
She knows readers might deem her relationship with her own son as "deeply inappropriate" and even "creepy" -- they are affectionate and even have their own song.
Many other women also described to Lombardi the "love affair" they felt with their boys.
But many, fearing a mother's love can be a "dangerous influence" close the door on their sons too early.
Some studies suggest boys are more fragile than girls, at least earlier in life. Sometimes that "hearty shove" is premature and can be devastating.
She cites a 2010 study of 6,000 children by psychologist Pasco Fearon of University of Reading that found those boys who were "insecurely attached" to their mothers were more aggressive and hostile in their teen years.
"Sons really need their moms and the last thing they need is withdrawal of support," she said.
Lombardi insists she doesn't want to turn boys into girls. "I don't think they are the same," she said. "The differences between them will always be."
But society has changed, and so have cultural constructs of masculinity and femininity.
Lombardi argues that sensitivity, tenderness and the ability to talk about feelings have traditionally been female characteristics, but they just might help boys in the future.
One study from Northeastern University predicts that by 2018, the social sector of the economy will gain at least 6.9 million jobs will require "brains over brawn."
"Our sons need to be ready for these jobs," said Lombardi. "They need communication skills and the ability to work in teams and have emotional intelligence."
Her son, Paul Lombardi, seems to be on the right path now that he is an adult, training to be a teacher in a residency tutor program at a Boston elementary charter school.
"I am the person I am today because of the values she instilled in me and the guidance and love she showed me," he said of his mother. "It's definitely unfair and stigmatizing to say a mother and son can't be close."
Both admit their relationship has changed over time.
"You don't treat a 23-year-old the same way as a 5-year-old," said Paul Lomabardi.
"I still feel like we have a connection," said his mother. "But I don't need to know everything that goes on in his life. We are adults now."
As for the book, Paul Lombardi said there were some surprises when personal anecdotes became public, but nothing too embarrassing.
"She went through the process and vetted with me," he said. "Like a good mom, she is protective and knows her boundaries."