Susan King, who is representing the Liberal Democrats in the Telford seat in next week's General Election, made the claims when defending party leader Tim Farron in a webchat with the Shropshire Star.
Early in the election campaign Mr Farron was questioned over whether he believed homosexuality to be "a sin", eventually confirming to the BBC that he did not.
When questioned over the furore Ms King said: "I do feel environmental influences are affecting reproduction. All the pollution is having an effect on our DNA and our population is changing and evolving."
She added: "There are a lot of feminising hormones getting into the environment and that has to be taken into consideration.
"It's affecting people's sexuality basically. People are at liberty to interpret how they want to live themselves.
"Phthalates, the chemicals used in making plastics, children's toys are affected. Everything that's getting into the environment is disrupting the way industrialisation has changed our living conditions, residues of all sorts of feminising hormones in the water supply from pharmaceutical etc which is affecting gender of fish stock etc."
"I've done a lot of research connected with water quality, and that is where I gained my political and media experience."
Telford election webchat: The Liberal Democrats' Susan King - as it happened
Ms King called her party leader "an independent thinker" who should be praised for "sticking to his principles", adding that she felt he had fought a good campaign.
"Tim has his finger on the pulse, he is very people centred," she said.
A Liberal Democrat victory in the seat would represent a major shock, as the party was fifth out of five in the 2015 election, more than 15,000 votes behind Conservative candidate Lucy Allan.
But Ms King, who hopes to move to Telford from Leicestershire if she wins, said: "The Tories give every impression that they are making up on the back of a fag packet.
"I honour Theresa May's honesty over the fact that social care is a mega challenge. But the way it has been broached is destroying people's confidence, making them very uneasy and very angry.
"The (Lib Dem) manifesto is geared to creating an open and tolerant society and a strong economy because without the strong economy all the high-minded measures for social care and supporting the NHS are founded on sand."