Penn hopes Milk will change the law
The star won an Academy Award for his portrayal of gay politician Harvey Milk in the critically acclaimed movie.
And now he is urging U.S. president Barack Obama to view the film in a bid to reverse the law and make same-sex unions legally recognised across the country.
Penn says, "Eventually we are hoping for a White House screening. I think this film will be one of the steps forward (in the fight for gay marriage). It will be part of the dialogue. But I think things are going to go forward with or without it.
"I was once asked to tell the difference between luxury and necessity for a human being. The right to equality for all, including homosexuals, is of course a necessity. That's why this right will become a reality and I think in its own way this film will be part of that.
"The need for tolerance, equality and so on is on the move, and will go on."
Homosexual couples in California were granted the right to wed last year (08) but it was revoked just months later after the passing of the Proposition 8 bill, which reversed the previous ruling permitting the unions.
On 5 March (09) a Californian court will hear arguments in lawsuits seeking to annul the referendum, with lawmakers due to hand down a ruling within 90 days.
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