Gender Equality vs. Gender Equity
Gender equality - which generally refers to "outcomes" - needs to be differentiated from gender equity - which describes "opportunities". Some people therefore want to "reserve" equity for use in the context of social development and process, as is not uncommon in the health sector and with reference to access.
"Gender (in-)equality" has therefore the advantage of giving greater emphasis on outcomes, results and impact. It also avoids an undesired element of relativism which often occurs with 'equity', i.e. that even "separate but equal" systems of opportunities and access are permissable, to accomodate different cultural systems and degrees of segregation between the sexes.
"Equality" stands more in line with a rights-based approach and refers to the absence of discrimination in terms of opportunities, resources, services, benefits, decision-making, power and influence. Increasingly, it denotes equality of outcomes and results.
"Equity" on the other hand refers more to fairness and justice in the distribution of opportunties and resources. It is therefore more dependent than "equality" on perceptions and definitions of what is fair and just in different societies. And of course such perceptions and definitions can be based on imbalances of power and exercise of rights between the sexes, to the disadvantage of women and girls.
All in all, "equality" appears to be the more encompassing term. It seems to accomodate better both the non-discrimination, equality of opportunity and outcomes aspects, as well as the distribution of benefits aspects, and therefore be the one with greater transformative connotations than 'equity'.