What is the burden of proving that male characteristics are more sexually aggressive and more physically aggressive than female counterparts?

In the absence of any supporting evidence, we cannot accept the government's assertions, which imply the broad generalization that males of all ages are larger, stronger, more sexually aggressive, and less likely to suffer physical injury from sexual contact than females. The government had the burden of showing why gender is a "sufficiently 'accurate proxy,' " Orr v. Orr, supra, 440 U.S. at 280, 99 S.Ct. at 1112 (quoting Craig v. Boren, supra, 429 U.S. at 204, 97 S.Ct. at 460), for prevention of harm arising from contact which inherently requires the participation of both sexes. Particularly when criminal liability rests on the adequacy of the government's justifications, something more than the government's bare assertions is required. We do not question that the government's assertions might be correct. Other courts have reached differing conclusions about the adequacy of the personal injury and pregnancy prevention rationales. ⁸ But it was the government's obligation

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