A significant number of the 300 Labour supporters and 200 Conservatives who took part in the questionnaire did not know how to put a condom on. Many incorrectly thought wearing more than one condom at a time was safer.
"A third of those who took part at the Labour conference got 10 out of 10, but those who got it wrong, got it really wrong," said Genevieve Clark, director of communications at the trust. "At the Conservative conference, fewer got all the questions right, but they mostly scored well overall.
"The sex education of many MPs is shaky, but we want them to make sure things improve for future generations."