Nominations have opened in the contest to succeed Anas Sarwar as Scottish Labour leader.
One of the contenders, Monica Lennon, has said the contest “reeks of misogyny and male entitlement”.
There has been speculation that she may not have enough nominations to formally become a candidate.
North East Scotland regional MSP Michael Marra, South Scotland regional MSP Joe Fagan and Ms Lennon, who is replacing Mr Sarwar as a Glasgow region MSP, have all announced they intend to run for the job.
The race was triggered when Mr Sarwar quit as Scottish Labour leader and an MSP to take up a role in Prime Minister Andy Burnham’s government via the House of Lords.
Party members and affiliated supporters are due to vote between August 28 and September 17.
The new Scottish Labour leader will be announced on September 19.
Before nominations opened, Mr Marra said: “I’m running in this contest to unite and renew the Scottish Labour party.
“Having spoken to and listened to colleagues across our movement it is clear we have to rediscover our sense of moral purpose.
“To offer hope again and to spell out what Scottish Labour is for, not simply who and what we are against.
“That means drawing on the strength and talent of all of our movement.”
Mr Fagan, who was previously the leader of South Lanarkshire Council, had earlier welcomed the support of MSP Paul Sweeney.
He said: “Paul understands that Scottish Labour cannot be a party of the Holyrood bubble.
“We have to bring our party back to the service of our movement and the people of Scotland.”
“All three leadership contenders have also written for the Scotland on Sunday newspaper, setting out their pitches to party members.”
On Sunday, Ms Lennon posted on social media saying there should be no “coronation or a contest without women”.
She said: “This ‘contest’ reeks of misogyny and male entitlement.
“That’s the road to nowhere.
“We’re not here for a social life or to win an occasional debate.
“We were created to win power for working-class communities and lead in government, not from the gutter.”
Read MoreJohn Lewis takes on Sports Direct with multimillion-pound fitness investment
Music, dancing and fireworks as Glasgow brings Commonwealth Games to a close
Israel says it has serious concerns with Hamas disarmament deal
England set to be hotter than Santorini as 35C heatwave sparks fresh health warnings
Ariana Grande pulls out of London musical to take a break from public scrutiny
Two universities merge to create the UK’s first ‘super-university’
