"On Oscar night, when Hollywood seeks to honor its best, Seth MacFarlane's monologue reduced our finest female actresses to caricatures and stereotypes, degrading women as a whole and the filmmaking industry itself," the letter stated.
Lowenthal and Jackson, both Democrats, asked Koch to respond. Academy spokeswoman Toni Thompson had no immediate comment.
In their letter, the lawmakers noted the Violence Against Women Act currently under debate in Congress and a resolution that the Legislature passed supporting the act's reauthorization. Better judgment is needed in the academy's future decisions regarding its awards show hosts and their material, they said.
"This should be a celebration of artists in the filmmaking industry, not an offensive display of disrespect toward women that sets the fight for gender equality, dignity, and respect back decades," they wrote.
A repeat hosting performance by MacFarlane doesn't look likely. Asked Tuesday on Twitter if he would host the Oscars again, he replied, "No way. Lotta fun to have done it, though."