Women and Wall Street have always had a rough relationship. Dozens of other complaints and lawsuits have been brought against banks over the years, from women all along the pay scale.
Morgan Stanley famously settled two suits for more than $100 million in 2004 and 2007, brought by thousands of female employees claiming they were denied promotions and equal pay because of their gender.
Smith Barney paid out $33 million in a similar suit two years ago.
Neither company admitted wrongdoing.
"Employers have become more savvy, so they often don't say blatantly discriminatory things to women, but there are many cases of more subtle forms of marginalization," said Dina Bakst, co-president of A Better Balance, a New York-based non-profit that advocates for women's rights.
While firms often have programs to help parents balance their responsibilities, women sometimes say the programs feel like a dead-end.
"Many women feel they are mommy-tracked and penalized for taking that path," Bakst said.
Nina Godiwalla, a former investment banker at Morgan Stanley who is writing a book about her experience as a woman in banking, said life for Wall Street mothers can be difficult.
"Breaking into that culture as a woman is really about you becoming as closely as possible one of the guys," said Godiwalla, author of "Suits: A Woman on Wall Street."
Mothers often felt pressure to prove their loyalty to the bank, she said, by participating on conference calls right before giving birth, or showing up at work the day after delivering.
"When you're that person who says, 'I'm taking three months off for my kids,' then suddenly your loyalty is in question," she said.
Women who want to start a family often decide to leave the financial business altogether, or opt for less stressful careers at regional banks or small investment funds.
But Hanna and Hazan-Amir said they are unwilling to let go without a fight.
Hazan-Amir still works at Citi, while Hanna said she would like her old job at Goldman Sachs back.
"I want other women who have had children to know that they have done nothing wrong and that they are not alone," she wrote in the e-mail. "Many do not want to stand up and fight against a big company like Goldman. Hopefully, when others see what I did, they too will have the courage to fight back."