A few days ago, many of us in the UK joined with women and men around the world in marking International Women's Day, celebrating the achievements of women and pledging to 'Be Bold for Change' on gender equality.

Sadly the worldwide Church has a long way to go before it can be accused of being bold for change in the way it treats women and girls. For centuries, people have continued to misuse the Christian faith and Scriptures to legitimise the systematic denial of women's human rights – their dignity, their security, their opportunity for life in all its fullness.

If, as Christians, we believe that being made in the image of God as male and female is a gift, then something is badly wrong when that gift becomes a weapon of oppression.

Something is badly wrong when one in three girls will be affected by domestic abuse; when widows are denied the right to inherit property in many societies; when gender-selective infanticide accounts for an estimated 1.56 million missing girls.

In my years working at Christian Aid, I have seen time and again the way in which women and girls carry the disproportionate burden of poverty. The way gender inequality hinders their chances of a safe future, in which they can not only survive but flourish. The way it prevents them from accessing the power, knowledge and resources that can help them thrive. The way cultural systems of privilege and patriarchy leave them open to violence and oppression.

The answer to this problem lies not in devising and delivering yet more charitable projects, necessary though these still are. It lies in tackling the root causes of gender injustice. This means finding ways to bring about just power relations between women and men, in which both are valued equally in their societies and communities, and can fully enjoy their human rights and fundamental freedoms.

Two years ago this month, Christian Aid set out to do exactly that, and invited a group of faith-based organisations and faith leaders from around the world to come together. Our conversations sparked the beginnings of a new initiative, Side by Side: a global movement of faith leaders, faith communities and faith-based organisations who are committed to work together for gender justice.

This was radical: although there are many wonderful faith-related initiatives on aspects of gender justice, there was no single global movement coordinating across faiths and across all the social, political and economic aspects of gender justice. By bringing together the work of the full range of faith actors and networks under a single umbrella, Side by Side aims to fill the gaps.

Already, Side by Side has 36 member organisations across the world, including the World Council of Churches, the Methodist Church of South Africa, the Episcopal Anglican Church of Brazil, the Movement of Dominican-Haitian Women, and Christian Aid.

Its members acknowledge that churches are not above reproach and that gender injustice can be perpetuated by social and cultural beliefs and behaviours which at times are endorsed by religious teachings.

Side by Side's aim is to mobilise and encourage faith leaders and organisations and people of faith everywhere to challenge and dismantle the religious, cultural, and structural blocks to gender justice, in their local contexts and more widely.

For example, the Kenya chapter of Side by Side is energetically advocating for the ratification of the two-thirds gender bill that would ensure increased female representation in parliament.

Today, March 17, I am thrilled to be attending Side by Side's official launch in New York. It deliberately coincides with the United Nations' Commission on the Status of Women, which is the main global body dedicated to promoting women's rights and empowerment, documenting the reality of their lives, and developing global standards on gender equality.

Side by Side is keen to build links with like-minded networks, and we are particularly excited to have been invited to co-lead the new UN-initiated Gender Equality and Religion Platform.

As I prepare to attend Side by Side's launch, I dare to be bold and imagine a world where gender inequality is no longer accepted in any social, political, economic, religious or cultural contexts. A world where violence against women and girls is eliminated. A world where power relations between men and women are completely equitable. A world where everyone, regardless of gender, has autonomy and agency over their own lives.

A world where, in the words of Side by Side, 'Gender is seen as gift rather than danger, a source of life and hope rather than oppression or fear.'

Jenny Brown is senior church advocacy adviser for Christian Aid.