GRADE assessment of the technical-scientific opinions on gender-identity legislation in Portugal

Aims. In March 2026, the Portuguese Parliament approved legislation reintroducing medical validation for changing the civil gender registration and prohibiting hormonal interventions in minors. Three technical-scientific opinions were submitted to the parliamentary public consultation: from the Portuguese Society of Clinical Sexology (O-SPSC), a Group of 224 health and academic professionals in gender-affirming care (O-G224), and the Board of Portuguese Psychologists (O-OPP). Methods. The Opinions were analysed as manuscripts under scientific peer review. Each theme was classified for verifiability, and the certainty of every cited reference was categorised with GRADE. Results. Of 90 references, 14 were non-classifiable. Of the 76 assessable, 89.5% (68/76) were rated Very Low or Low certainty. Only eight carry relevant probative value, one Moderate and seven Low-to-Moderate, and none directly measures the outcomes under debate. Independent systematic reviews, absent from the Opinions, rate the evidence as very-low certainty for psychological benefit and moderate-to-high for some physical harms of hormonal interventions in minors. Conclusions. Across the three Opinions the cited evidence is directionally selected: the highest-quality systematic reviews in the field are absent, and an undeclared institutional overlap exists between the O-G224 signatories and the O-SPSC governing bodies. The mobilised evidence is predominantly of low certainty and does not, on its own, establish that prior clinical assessment should be dispensed with in social or medical transition. Taken together with the higher-quality literature absent from them, the evidence is insufficient for definitive conclusions in either direction, and argues for clinical caution rather than for either legislative position.