Ms Sturgeon insisted she was “just not going to get into this debate” as she was probed on defining a woman.
Speaking ahead of Thursday’s local elections, she argued that to “oversimplify” the debate around trans rights would cause suffering to a vulnerable group.
The SNP plans to allow Scots to change their legal sex by making a declaration.
And given the crunch vote looms this week, the debate has become a doorstop issue.
Asked to define the word woman, she said: “I’m not going to. I’m just not going to get into this debate at a level that’s about simplified and lurid headlines.”
First Minister of Scotland Nicola Sturgeon poses with local candidates while on the local election campaign trail in Arbroath
Russell Cheyne
First Minister of Scotland Nicola Sturgeon
Russell Cheyne
She added: “Trans people are amongst, possibly the most, stigmatised and discriminated-against minorities in our society.
“And every time we oversimplify this debate, trans people actually suffer.
“I think it’s important, they’re such a tiny minority, that we actually take the issues around protecting and enhancing the rights of trans people seriously.”
Some trans activists argue that a transgender woman is literally a woman, regardless of their biological sex.
But For Women Scotland said politicians should have no issue with using the dictionary definition of “adult human female”.
Director Susan Smith added: “This is a First Minister who claims to stand against sexism in politics, yet can’t bring herself to meet and talk to women harmed by her policies.
“Her track record on dealing with harassment and abuse in her own party leaves much to be desired.
“Her self-ID proposals are not about ‘trans people’ but for anyone who chooses, for whatever reason, to change sex in law.
“All the evidence of harms to girls in school forced to use mixed-sex facilities, to women in prison, to the hundreds of girls who are being affirmed as the opposite sex and set on a path to lifelong medicalisation is to be dismissed and discounted.”
Ms Sturgeon’s interview with The Times came weeks after Labour leader Sir Keir Starmer struggled to say whether he believes it is possible for a woman to have a penis.
Prime Minister Boris Johnson has said that the “basic facts of biology” are “overwhelmingly important” in distinguishing between a man and a woman.