The aptitude tests used by the RAF, GAPAN and others are entirely devoted to assessing the motor skills and spatial awareness abilities of a candidate. These skills are the fundamental requirements of a pilot, and can't be 'traded off' against other skills or abilities, no matter how useful. At the end of the day, you still have to be able find your destination airfield when your navaids have packed in, to get your aeroplane on the ground with half the engines out, on a sh*tty night in the rain and howling crosswind, while remaining aware of the relative positions of traffic in your vicinity. This is not negotiable.
It's not just a 'claim', it has been demonstrated over many years of testing that, in general, males are better at these skills than females. That doesn't mean that no women have them, or that the most talented women aren't at least as talented as the best men. But it does mean that you are going to struggle when you aim for equal numbers, as you would have to attract a far greater proportion of the existing suitably-able women than men. It's unlikely to happen.
Remember, the fundamental tenet should be 'equality of opportunity'. Any person, regardless of race, gender or whatever, should have the chance to qualify in any trade, but some trades have demands that cannot be waived for the benefit of political correctness. Within the limits of current technology, the need to have the aptitude to fly is as basic as the need for a pilot to be able to see and hear. It's a shame that more wannabes of either sex don't get themselves tested before potentially wasting huge amounts of money!