Margaret Thatcher destroyed my career structure for fairly petty reasons (long boring story about the government of London and her hatred of Ken Livingstone which ends with there being no city-wide educational authority) so I'm a little biased, but I think it's fair to say that she's widely seen as one of the reasons why Britain has not subsequently had a female prime minister. Too many people have bad memories of her.
Re the presidency, I'd hope that any candidate will be elected on the issues and ability to govern, not gender or looks.
