Some men may choose not to recycle or buy reusable cotton bags because they are worried people will think they are gay, a new study claims.
Scientists suggested looking after the planet was seen as a typically "feminine" thing to do which fits in with a woman's traditional role of being a caregiver.
This perception may hold men back from doing things such as buying a keep cup or turning off the air conditioning that could ultimately help the environment, according to the study published in Sex Roles.
Janet K Swim, professor of psychology at Penn State University, said: "There may be subtle, gender-related consequences when we engage in various pro-environmental behaviours.
"People may avoid certain behaviours because they are managing the gendered impression they anticipate others will have of them. Or they may be avoided if the behaviours they choose do not match their gender."
In three studies that involved 960 participants, researchers looked at the perception of men and women engaging in "feminine" and "masculine" behaviours. During the first two studies, participants read a fictional summary of what someone did that day which included typically male or female pro-environmental behaviours.
They then rated on a 10 point scale whether the person had masculine or feminine traits and guessed their sexual orientation. The results suggested that when people did activities that conformed to their gender they were seen as more heterosexual than those whose behaviours did not conform to their gender.
This suggests participants believe traditional gender roles could give clues about someone's sexuality.
"Reflecting the tendency to see environmentalism as feminine, all the people were rated as more feminine than masculine regardless of the behaviours they did," Professor Swim said.
"If being seen as heterosexual is important to a person, that person may prioritise gender-conforming over gender-nonconforming pro-environmental behaviours in anticipation of how others might see them."
In the third study researchers looked at whether people avoided others in the room depending on their environmental behaviour preferences. They found that men were more likely to distance themselves from women engaging in masculine behaviours.
Professor Swim said: "We were surprised that it was only women who experienced being avoided if they engaged in nonconforming gender-role behaviours.
"We can't say why this is happening, but it is a social consequence. Women may be experiencing this negative feedback and might not know why."
Scientists say policy makers and activists looking to promote environmental behaviours may want to consider gender roles as a potential barrier.