Less than 30% of engineering grads here in Canada work as engineers. When you interview 4th year students, more than 90% of them intend a career in engineering, so not all of them are leaving the profession by choice- most are leaving because they cannot find an entry-level position to get a toe-hold in the profession. That's unlikely to dramatically improve in the next five to ten years.
Despite the poor capture of eng grads into engineering, eng school enrollments are rising year after year here, at a rate greater than economic or population growth. That is important information that every prospective engineering student should know before making the decision to enroll in an eng program. The stats are better in the US right now, but the capture of eng grads into eng careers is sagging there too. Engineering school has long ago ceased to be a ticket to a career as an engineer, though eng grads are sought out for other occupations.
When I was at school in the 80s, my chem eng class was about 30-35% female. The ratio increased toward graduation- guys failed more frequently than girls. Current chem eng classes at my alma mater are about 50% female. Mech, elec and computer (geek eng) are still almost free of females (5-10% female at most), but civil and systems/industrial are at least 1/3 female- that hasn't changed over the past 20 years or so. There is no reason in my mind that we should be taking active steps to make all these programs 50% female, any more than we should be concerned that there are now more female doctors graduating than there are males.
Unless your granddaughters have more than just an aptitude in math and science, encourage them to keep their options open by not dropping advanced math and science courses too early- that's essential. But like all people, they should seek out and pursue their passion- a mere aptitude may lead to a passion, but mere aptitude is insufficient for success. If technical problem solving is that passion, engineering might still be a good choice as an education.
As to what they'll end up doing for a living, that's years hence and nobody can predict it for them now. At present, anything that leads to a good white-collar salary here is oversupplied with entry-level candidates- with one exception: medicine. Medical schools and the provinces who fund them still control the number of residency spots to more closely match demand. Over 90% of people in Canada with medical degrees work as doctors, and that's not because a doctor's education makes them unqualified for other work.