Two Green Party candidates have launched a High Court battle for the legal right to become job-share MPs.
Sarah Cope, 36, and Clare Phipps, 26, wanted to stand jointly for the role of MP for Basingstoke, Hampshire, in the May 2015 general election.
They planned to share an MP's responsibilities as Ms Cope is the main carer for two young children and Ms Phipps suffers from a disability.
Their nomination was rejected as invalid by the acting returning officer for the Basingstoke parliamentary constituency because it was two people seeking the one seat.
They are applying for permission to bring a judicial review challenge, arguing the rejection breached both human rights and equality laws.
With law firm Leigh Day acting on their behalf, they are contending that the decision to prevent them standing jointly for office amounts to a disproportionate and unjustifiable interference with their legal rights.
Their nomination was supported by the Green Party, which has had job-sharing as its official policy since 2012.
Ms Cope, a mother of two, has been an active member of the party for over a decade and is the chairwoman of Green Party Women.
She has developed party policy on maternity services, breastfeeding, childcare as well as prison reform.
Ms Cope said: "The 32 million UK women make up 51% of the population. At the moment however, over 450 of the 650 MPs in Parliament are men.
"We need to change the culture of Westminster and stop wasting so much untapped talent. Allowing MPs to job-share is a relatively minor change which could bring about huge benefits."
Ms Phipps, who job-shares a position on the Green Party executive, is researching gender and health as part of a part-time PhD.
Since 2009 she has suffered from a disability known as idiopathic hypersomnia, a chronic condition which means she sleeps for around 12 hours a day.
Ms Phipps said: "The concept of job-shares has been accepted for some time now, and in a wide array of fields - from doctors, to teachers, to judges.
"It is a sad indictment that to get this basic right for MPs we are forced to take our case to court."