Never have we had a perflower female turn male and out of hundreds of plants it was rare to find a hermie. 1 in a 100 maybe.

If you have female perflowers take it to the bank. Unless you stress them badly it has never failed us.
LOC NAR on probation Reviewed by LOC NAR on probation on . Are preflowers reliable to ID sex This is out of the Marijuana Growers Guide- "The presence of premature female flwoers does not assure that the plant is a female, but premature male flwoers almost always indicate a male plant. Unfortunately, it is much less common for male plants to develop premature male flowers than for female flwoers to appear on ether plant. For example, in one garden of 25 mixed variety plants, by age 14 weeks, 15 plants showed well-formed, premature flowers with raised stigmas. Eight of these Rating: 5