I have been called a pagan and a radical feminist, foolish and naive. My crime? Casting a woman in the role of God in the mystery plays to be staged at York's Theatre Royal.

I certainly did not set out to create a controversy. I didn't even set out to cast a woman in the role. The original intention was to have a professional actor to play God. Then we started auditioning for the amateur actors who get involved in the play - 120 local people take part. At the auditions I met Ruth Ford, who runs a local shop. She struck me as someone who would bring a tremendous amount from her own life to the role - compassion, humour, joy, love and care - all the attributes one might hope to find in God. I did wonder about whether she could embody God's wrath, but then I thought wrath can't just be a man's domain.

The way I see the role played is all about the personality of the person playing it - not about their gender. There won't be any feminising to the text, which is based on the original 13th-century text, and was revived in 1951 as part of the Festival of Britain, and has been performed in York every four years or so ever since. In the past, God has been played by a child, and by a disembodied voice - this is just another way of interpreting the role.

The criticism we have had from some churchmen seems to be much more to do with their internal politics than our play. It seems that seeing a woman in this role at this particular time is making them ask fundamental questions about their church and their beliefs. It is a sensitive time for the church as it wrestles with its own internal problems over women, and I'm afraid we have touched a nerve somehow with this casting.

The task for Ruth in playing this part has to be to make people ask questions, about themselves, about their assumptions, their pre-conceptions about how they see God, and even how they see men and women. I'm not interested in maintaining a childlike illusion of God as an old man with a long white beard. The essential thing is to make this powerful medieval play as accessible and relevant as possible to a modern audience.

I'm sorry if people have been offended by the choice of Ruth for this part - a lot of people have been delighted by it. I hope nobody will let their worries stop them coming to York Theatre Royal to experience her playing in the Mystery Plays. I would reassure people that we do take our responsibilities very seriously, and we are not out to shock or upset people. I hope that audiences will come with an open mind, and will leave feeling uplifted and inspired by the power of the play and the performance.

The writer is artistic director of York Theatre Royal.