I think it's an absolutely awful thing to say to someone, it really is. It shouldn't matter if you already have one, you want more and probably always wanted more before you knew that you would hvae fertility issues. My neighbour had twins back in October last year after secondary infertility troubles after their first DD was born 6yrs ago and they had to go throguh IVF to even get the twins and she said she coped that alot - and even once she was finally pg again and suffering horrendous morning sickness people still said awful things when she complained about her m/s and now, when she talks about going through it all again in the future (cause they always wanted a really large family) it's gone back to the 'oh but you have 3, isn't that enough now?' Its cruel.