Apart from the equality issue, men are now being actively encouraged to enter the pre/ nursery school area as well as primary schools. It is thought that this gives the children a more balanced view of the world and provides male role models . The male teacher will have an enhanced CRB check just as the female teachers have . Your husband is being totally unreasonable , can you imagine the row that would blow up if he refused to send the child to school because he disapproved of a teacher's ethanicity ? he has no more reason to refuse to send the child because he does not approve of the sex of a teacher. Good schools, especially pre schools, are hard to find and they are of huge benefit to the child, please try to get him to see sence.
If your husband has such a distust of the male sex it will go far beyond choice of a pre school , it will blight your child for life ! it needs to be sorted now for the sake of the childs future.