Sel if you lived in Manchester, actually you could pick and choose. If you are over 60 or under 16 and a Manchester resident, you can swim for free, subsidised by our council tax. This isn't discrimination, but part of a wider initiative to promote a healthy lifestyle for children and older people. The money to fund this used to come from central govt, but was part of the cuts.
Manchester run a swimming programme which offers unisex, female only or male only classes. They also offer mixed swimming, ladies only, under 5s, adults only and aqua natal. So there's something for everyone. They offer a similarly comprehensive array of fitness programmes.