Many women have little power at home - and younger women even less, say Sabine Garbarino and Frances Hansford.
As the euphoria around September's UN Sustainable Development Goal summit begins to fade, attention is fast turning towards how to start acting on the SDGs. Their ambition is laudable - as is the recognition that they are interrelated in myriad and complex ways.
Take Northern Nigeria. One primary aspect of women's roles there, as in many places, is responsibility for the day-to-day care of their children. And yet the way many Northern Nigerian homes are managed leaves women without the power and resources to carry out this role effectively.
Data we collected from a sample of almost 6,000 mothers in four northern states showed that 97 per cent of women needed permission to go the nearest health facility alone, 46 per cent had no say in food purchasing decisions and 34 per cent had no say in decisions regarding their children's healthcare. In these households, the woman's husband made those decisions alone.
This may come as no surprise - research shows similar realities in other parts of the developing world. But the impact of a woman's age is an important and less recognised factor: young mothers have especially low levels of autonomy in the home. This should be taken into account in development programmes.
Limited bargaining power
The data in our Northern Nigeria study shows a strong association between a woman's age and decision-making power. Young mothers, often in their teens (the average age at first pregnancy in our sample is 17), have little say in household decisions, particularly if they are much younger than their husbands. In our data, the average age gap between husbands and wives is 13.5 years.
Marriage at such an early age constrains the opportunities open to women: young wives are less likely to finish their schooling and to earn an income. This further limits their bargaining and decision-making power within the home.
When mothers are disempowered in this way, they have less capacity to care for their children. They are less likely to be able to attend health and nutrition services for themselves and their children, and their ability to adhere to advice on sound child feeding practices can be inhibited.
Younger mothers also have less decision-making power than older women: many mothers in our study reported that they were prevented from adopting new behaviours, such as solely feeding their babies with breastmilk, by their own mothers or their mothers-in-law, some of whom are resistant to changing behaviour.
Having no say in how household resources are used may also leave women without cash for transport to a clinic - an important barrier in rural areas.
Studies in other parts of the world, including Bangladesh and India, also link maternal empowerment with child nutrition outcomes.  So what can be done to better enable mothers to care for their children?
First, engaging and educating men on the importance of good nutrition is key. Following recommendations from our study, the Working to Improve Nutrition in Northern Nigeria programme has introduced education in mosques to help fathers understand that paying attention to the health and nutrition of their wives and young children translates into better life chances for their children.
Other programmes and organisations, such as the Adolescent Health and Information Projects and the development Research and Projects Centre, have similarly involved traditional leaders in educating men about family health in Northern Nigeria. Elsewhere, the Engendering Men: Evidence on Routes to Gender Equality (EMERGE) project is building a body of evidence on the importance of involving men and boys in initiatives to promote gender equality.
Second, it is important to support programmes that address systemic issues around household disempowerment - preventing child marriage, for example, or delaying first pregnancy and ensuring that girls finish their schooling.
Doing this can reduce the age difference between husbands and wives, and increase the choices available to girls and young women. The ultimate goal is to increase women's decision-making power and autonomy in the home. Girl Effect Nigeria is just one organisation working to achieve this.
Beyond the household level, greater female representation in civil society organisations is key: to promote and defend the rights of women, and to ensure that health and nutrition services are delivered in a way that responds to the different needs of men and women. In Nigeria, the recently created federal- and state-level Food and Nutrition Committees - charged with coordinating a multisectoral response to malnutrition - have few or no female members.
We need to start looking at child malnutrition through a different lens: rather than pointing the finger at 'negligent' mothers somehow failing to provide good care for their children, we should be asking how we can address the power imbalances that prevent them from acting.
Gender inequality is certainly not the only factor underlying malnutrition - but it's an important one. If we're serious about making progress towards SDG goal two on ending global hunger, perhaps a good place to start would be SDG goal five: achieving gender equality.
Sabine Garbarino is a senior consultant and Frances Hansford is an associate consultant, both specialising in development and gender, at consultancy Oxford Policy Management in the United Kingdom. They can be contacted via @OPMGlobal