I believe that calling a professional a girl/boy is wrong. This applies people who have a doctorate, but anyone who you are doing business shouldn’t be referred to as girl or boy. If I am at work, it’s a grown-up job. I won’t call you a boy/girl and I expect the same with respect in return. I need the respect that is due to any adult.
Some of my friends who are university professors have found that it’s harder to call a woman professor than it is to call their male counterpart. The same goes at the hospital. People tend to say doctor when it’s a man and use the first name without the title when it’s a woman. I’ve made that observation upon my many patience-testing excursions to waiting rooms. This is probably because we undervalue the role of women and we do so automatically without forethought so it may not even be our intention, it’s just an automatism. Unfortunately, it is automatism that are the most dangerous. We shouldn’t be okay with undervaluing ourselves or anyone else. Words have meanings whether you like it or not, simply not calling someone ‘girl’ or a ‘boy’ isn’t that hard.