HI
Adding to others, No to lady employees will falls under the category of discrimination. If you refer the clause given by International labour organisation, it says "No person shall be subject to any discrimination in employment, including hiring, salary, benefits, advancement, discipline, termination or retirement, on the basis of gender, race, religion, age, disability, sexual orientation, nationality, political opinion, or social or ethnic origin". So if you put in a policy like you mentioned will result in unwanted complication. if you don hire an female is something different because of the nature of job but avoiding is not fair. Hope you will understand the sequence.