I've heard some arguments both for and against this idea. So I'm going to list as many pros and cons as I can think of, but I'm sure my readers will come up with a few more.
- Women are disadvantaged and discriminated against. Quotas help close that gap.
- Quotas keep a lid on unintentional discrimination, where employers hire people similar to themselves to fill positions without realizing it.
- Whether you're talking about politics or business, quotas help ensure the voters or customers are more accurately represented (since the quotas would better mirror a cross-section of society) and that their points of view are more likely to be heard.
- Hiring quotas would force companies to recruit women more heavily, so there could be some trickle-down effects such as implementing more women-friendly policies or promoting fields such as engineering or politics to girls at an earlier age.
- Often men do not consider women's interests, whether that's in campaigning, managing, or selling. They should, but they often don't. If there were more women, it would be much easier for them to voice their objections.
- There would be more female role models for women in every field.
- Profits would grow. There are plenty of studies to show that investing in women pays off in a big way. It's not a stretch to imagine that innovation and the economy would grow, too.
- Strict numbers don't account for individual differences and mitigating circumstances.
- A more qualified candidate could be passed over in favor of someone who fits the quota requirement.
- Depending on what the actual numbers are, quotas don't take into account women's choices. Some women may choose to spend time at home or in different fields than men (you could make a counterargument that women are socially pressured to make certain choices, but that's another topic), often leaving the workforce for years at a time.
- Some countries that have quotas in place still experience gender equalities such as unequal pay, so they don't solve everything.
- The inevitable paperwork, legal headaches, and corporate culture adjustments could make for a painful transition.
- Women might feel pushed into certain roles or expectations in their workplace that they don't want to fill (e.g. being pressured to work full-time in order to make the numbers look good even when they'd rather work fewer hours).