In the consultations about what will replace the millennium development goals (MDGs) when they expire in 2015, there is pressure on politicians and political commentators to come up with the next "new" idea.

The lack of focus on inequality was a key limitation of the MDGs and, rightly, this has become a major priority for the post-2015 agenda. But the discussion about inequality is evolving in a way that may undermine, and even reverse, the international commitment to gender balance. There are welcome efforts to define new ways of measuring income inequality, but gender and other social inequalities are invisible within these measures (pdf). And, while greater attention is finally being paid to social inequalities, there is a worrying tendency to treat gender as just one of many inequalities that generate poverty and exclusion. There is even a proposal to replace the current gender equality goal with a general and so far undefined "inequalities" goal.

The fundamental premise behind the demand for a standalone goal is that gender is not just one of many inequalities but the most pervasive.

First, it places women at a disadvantage at every level of income and within every disadvantaged group, including those disadvantaged by caste, race and disability.

Second, gender is structured into the organisation of social relations of production and reproduction of every known society, in the same way class inequalities structure capitalist societies, racial inequalities structure South Africa, and caste inequalities structure India. In much of the world, there is a marked inequality in the responsibility that men and women take for the daily unpaid care work within the family and community, in their ability to mobilise resources and access opportunities to contribute to family and community on both a paid and unpaid basis, in the value and recognition given to these contributions, and in their capacity to exercise agency on their own behalf.

Third, the structural nature of gender inequality means it is central to meeting development goals. Wide-ranging benefits accrue to society when gender equality is taken seriously – and corresponding losses when it is not. A recent review of the literature (pdf) found robust evidence that countries with greater gender equality in employment and education were likely to report higher rates of economic growth and human development. The reverse relationship – that economic growth contributes to gender equality – was far weaker and less consistent.

For all its limitations, the MDG on gender equality and women's empowerment demonstrated the impact that a dedicated gender goal can have – as a mechanism to hold governments accountable for their responsibilities to women, as an advocacy tool for organisations concerned with gender equality and human rights, as a line of defence against forces of conservatism that threaten to reverse equality gains, and as a catalyst for funds and measurement in relation to work around gender. Any new framework that fails to include gender as a distinct goal would significantly backtrack on previous commitments (pdf), sending a clear and dangerous signal that the issue is no longer a political priority.

While mainstreaming gender across the post-2015 framework will be vital, not all targets can be adequately slotted under other goals. For example, maternal mortality was an important element of the MDGs, but under a health goal interventions focused on service delivery (pdf) rather than on the deeper causes of gender inequality – unsafe abortion, early marriage, violence against women, male dominance in household decisions about spending on health, and so on.

What should a standalone goal look like? This is clearly likely to be the subject of considerable debate, but we will focus on criteria that seem consistent with the discussion so far. The goal should: reflect the priorities of marginalised women and girls; address the structural causes of gender inequality; be accepted and acted upon by national governments and the international community; and address issues that cannot, or should not, be placed under other goals. Among the gender-specific injustices that do not fit neatly into other goals are ending violence against women, the single most important issue identified by women's organisations across the world; reproductive health and rights, including a continued focus on maternal health; and women's unpaid work burdens, a major factor in curtailing their participation in the public sphere.

Among the demands most likely to have a transformative impact on structural inequalities are women's economic empowerment through ensuring fairer access to productive resources and employment opportunities; women's political empowerment through ensuring greater representation in formal and informal decision-making positions in public and private sectors at local, national and international levels; and women's social empowerment by strengthening their capacity for collective voice and action through support for organisations dedicated to women's rights and gender justice.

The MDGs taught us that, without addressing the underlying structural causes of gender inequality, progress is likely to be uneven and prone to reversals. To abandon these lessons, backtrack on previous commitments, and remove a dedicated gender goal – while at the same time embracing the concept of inequality – would be a cruel and harmful irony.