I’m currently at the International Congress of Actuaries in Cape Town, and it’s amazing what you learn. For example, today I learnt that whilst mammals have X and Y chromosomes, with women having two X’s and men having an X and a Y, birds have W and Z chromosomes with male birds having two Z’s and female birds having a Z and a W. Now this is interesting enough (to me), but what is even more intriguing is that whilst for mammals females tend to outlive males, for birds the opposite is often true. This is thought to be because having two of the same type of chromosome offers some protection from genetic damage to one or other of those chromosomes. It also suggests (again) that it will be very difficult to bring longevity for men up to that of women. Now, isn’t that interesting?