I can totally understand your point... but i agree your sig is unfair. Saying it in one post is different to putting it in your signature. I'm not TTC but I would be so happy if I had a little 'surprise' so I find it quite offensive. I hope you get your BFN as you don't seem to want a baby...
Not picking on your response specifically webbykins, is just yours is that last one and i'm too lazy to go back and quote someone else.
I'm in a similar situation as webbykins and would love to be pregnant although i'm not 100% actively TTC.
Personally i don't find her signature offensive at all. As Amy (nikky0907) said, this section is mostly avoided by those having difficulty conceiving mainly because there are so many surprise pregnancies in this section. My first thoughts upon reading her signature were that she is willing to face up to responsibility if she is pregnant as it seems from her first post but that she would prefer not to be pregnant. I'm sure many of those who had surprise pregnancies at a young age would have preffered the test to be negative. I don't think she meant any offence to anyone by it. Just that she feels unready to have a baby now, but would cope if she had to.
In answer to your original question, i don't think it's cruel to bring up a baby at a young age but it would be very difficult xx