One sort of rational explanation for a lower wage is that females might get pregnant and need leave for that, although that probably does not justify the difference (I haven't done the calculations). That is also why insurance prices offered to females / males are often different insofar the law allows it.
That's an outrageous reason to discriminate against someone. A man also might take leave after their child is born. A woman might not get pregnant. Someone might be predisposed to sickness, but you still wouldn't be justified in using your crystal ball and tarot cards in order to pay them a lower wage.
This is a matter of statistics and risk evaluation, it is a fact that health insurance companies take the risk of pregnancy into account when calculating the insurance premium, whether you like it or not. In the same way there is a risk to the employer and in principle it is fairly easy to assign a cost to it, too. For example, assume an employee makes 40k a year and will take 3 years off during her work life, due to pregnancy (not uncommon in Europe and often with almost full compensation). Assume she works 40 years, then the cost per year is 3k, so she should actually be compensated with ~37k per year. This is the most naive calculation, if you knew statistics on how many men vs. women take paid leave because of children and so on you can of course come up with a much better cost model.
If you assume that a company acts rationally there is no reason for arbitrary discrimination, but every reason to adjust wages according to possible costs. I'm sure in the case of wage inequality, this is not the main reason however.
Don't brush your teeth for a week, drink a diet coke immediately followed by a coffee right before the interview. This will give you the appearance of someone with bad teeth (and it is really bad for your teeth. Take something for the smell. Don't make a habit out of it).
Then you will know whether there is discrimination based on medical conditions or not.
We all know the outcome of this.
The same applies to appearing sick otherwise. I have a particularly white skin. Under the wrong light it can even appear a little gray. Interviews in sunlight go significantly better than under UV light, and I'm pretty sure it's-because they think I'll be ill soon.
Management, everywhere I've ever worked was a band of old boys, playing social poker with eachother. Even the bosses I've had that were minority themselves discriminate. And they were minority only in genes, for example one was a "Turk" ... A christian, grew up in Boston. But yes he's tall and darker and has that broad face. Enjoys football. Discriminates based on religion (granted, given what muslims are doing to Christians in Turkey, I understand. Especially after him showing me some articles concerning the still existing Turkish Armenian Christians)
But it's not like other bosses were different. The problem is the type of person that tends to fill middle management, nothing else.
Since I've started working the main difference is that they lie about it really hard these days.
