Inappropriate: Ellen Pao claims she received pornographic materials from her male colleagues while working for Silicon Valley venture capital firm Kleiner, Perkins, Caulfield & Byers. Pictured above outside court on Tuesday

The trial of a high-profile sex bias lawsuit in Silicon Valley began Tuesday with a lawyer for a former junior partner at a venture capital firm claiming his client was denied a promotion because of her gender and then fired when she complained.

In his opening statement, lawyer Alan Exelrod said plaintiff Ellen Pao was discriminated against in the male-dominated culture of Kleiner, Perkins, Caulfield & Byers — the defendant in the case that has sparked debate over the treatment of women in the high-tech and venture capitalist arenas.

Exelrod said Pao, 45, had received erotic poetry and sketches of nude women from a senior partner at the firm, and another male employee interfered with her work when Pao broke off an affair with him.

The firm has denied wrongdoing and said Pao was a poor performer who didn't get along with her colleagues. An attorney for the firm was expected to give an opening statement later in the day.

Pao is seeking $16million in damages. The trial in San Francisco Superior Court could last four weeks. The jury includes five men and seven women.

Venture capital firms provide much of the startup funds for tech companies and have a reputation as being even more insular and male-dominated than the companies they help launch.

'This case is a wakeup call,' said longtime Stanford University law professor Deborah Rhode, who teaches gender equity law. 'The case has sparked a much-needed debate about gender inequality regardless of its merit.'

Women hold 15 to 20 percent of the technology jobs at tech giants Google, Apple, Facebook and Yahoo, according to disclosures by the companies.

The firms acknowledge needing to do more to hire female engineers but largely attribute the problem to cultural issues that discourage girls and young women from taking classes needed to pursue careers in computer coding and website design.

High-stakes: Pao is currently suing her old firm for $16million, claiming she was discriminated based on her gender. Pictured on the right during her days working at Kleiner Perkins with senior partner John Doerr, who she served as chief of staff to

Venture capital firms are even more slanted toward men. A 2011 survey by the National Venture Capital Association found women accounted for 11 percent of investors.

A study released last year by Babson College in Massachusetts found that women filled just 6 percent of the partner-level positions at 139 venture capital firms in 2013, down from 10 percent in 1999.

Kleiner fired Pao in 2012 — six months after she filed her lawsuit. She had been hired in 2005 to serve as chief of staff for senior partner John Doerr, who helped direct early investments in Google and Amazon and who currently serves on President Barack Obama's Economic Recovery Advisory Board.

Pao left the administrative position with Doerr in 2010 to become a junior partner with full-time investment duties.

Pao claims she was excluded from important meetings, email chains and company dinners because women 'kill the buzz' of such festive occasions, according to the lawsuit.

Long fight: Pao's trial against Kleiner Perkins could last as long as four weeks. Pictured above with her attorney Therese Lawless (left) during a lunch break on Tuesday