From earliest times, people have longed to be sure they will have a baby of a particular sex. There are innumerable ' old wives' tales' offering advice on how to have a girl rather than a boy or vice versa. Now science is entering the field with gels to apply, advice on timing, methods of sperm separation and, in the animal world, the pre-sexing of embryos before implant. In the USA there are even some mothers who have tests to find out the sex of their baby and then seek an abortion if it's not what they want. What are the ethical implications of such procedures? How well do they work? What are the risks? If the use of some methods becomes widespread, will this upset the balance between the sexes? Would more people choose to have boys than girls?-Man Alive has commissioned a special poll to hnd out. Jeanne la Chard and Nick Ross investigate.