Anas Sarwar has accused the UK Government of taking the "wrong approach" after it blocked gender reforms passed by MSPs.
The Scottish Labour leader and the majority of his party voted in favour of the Gender Recognition Reform (GRR) Bill at Holyrood last month.
But the legislation was yesterday prevented from becoming law after Tory ministers claimed it would undermine the UK-wide Equalities Act - an argument furiously denied by the Scottish Government.
Making his first comment on the row since it erupted on Monday, Sarwar claimed "we don't need a constitutional fight on this".
Splits within Labour on GRR emerged last weekend after UK Labour leader Keir Starmer admitted he had "concerns" over plans to allow 16 and 17-year-olds to change their legally-approved gender.
Sarwar, who backed the age reduction, said: "I don't think this is the right approach from the UK Government, I think it is the wrong approach.
"We don't need a constitutional fight on this. We don't need a culture war on this, which is so often the case in Tory politics.
"Instead we need a grown-up, pragmatic, good-faith approach going forward so we can protect the rights of trans people while also maintaining the protections of single-sex spaces."
Labour MSP Monica Lennon told the Record yesterday that Starmer had undermined the Scottish party after he criticised the GRR bill.
She she was "very disappointed" with the UK Labour leader and urged him to be "better briefed" on areas debated in the Scottish Parliament.
Starmer had said: “I have concerns about the provision in Scotland, in particular the age reduction to 16 and in particular the rejection of our amendment in relation to the Equalities Act.”
Pressed on whether he thinks someone of 16 is old enough to decide to change their gender, he replied: “No, I don’t think you are.”
Asked about Starmer's comments, Sarwar said: "Where Keir and I agree is we are both absolutely supporters of devolution.
"We both support reform of our gender laws across our country, we both believe we need to remove the inhumanities in obtaining a GRC."
He added: "How Keir decides what the laws look like in other parts of the UK is absolutely a matter for the UK party.
"But where there is agreement is around protection of devolution, around reform, around protection of single-sex spaces, and around the inhumanities of obtaining a GRC."
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