Because bombs have a low effefctive range, and a high shrapnel range. (15 meters in fact), girls are psychologically hindered in their throwing ability.
Scientists suggested that the inept throwing motion of girls arises from three signature feminine motor traits: self-consciousness, inhibition, and kinetic dis-unity of the body.
"Taken together, our results therefore suggest that given a similar amount of motor training, males benefited more than females in the performance of the trained movement sequences. This effect was age dependent with the male advantage becoming significant in the post-puberty group, the 17-year-old participants. Moreover, males from all three age-groups were found to evolve significantly larger delayed (consolidation phase/between session) gains, and these were well retained for 6 weeks. Thus, the male advantage was most significant in the post-training motor consolidation and retention phase; the current results suggest therefore that males, especially after adolescence, may have an advantage, over females, in procedural memory consolidation."