There's not much difference in speed and strength between males and females in the youngest junior age groups. I was watching Becky Willoughby's videos of the Coniston Gullies races, where she was positioned a little way up the ascent route (and so towards the end of the descent). In the under-9's, five girls came past on the ascent before the first boy, although on the descent there were two boys in the leading positions, ahead of five girls. In the under 12's, Bleu Bailey was leading on the descent, although the results show that she was just beaten by a boy at the finish.