Ok, before I start, I have to say that I know this is advertising. I am aware that Nike are trying to sell me their brand and they are cynically tugging at my heartstrings to do so. BUT at least the message is better than the P&G Sponsors of Moms advertising that I ranted about earlier this year. Advertisers should take note that women are not all mums and those of us who are mums don’t all define ourselves by our “status” as a mother. I am a mother by an accident of reproductive luck. It is not something that requires particular skill. I just got lucky. It does not…