Rollmops, you need to understand the reality of adoption in the UK. Babies are not adopted at birth. Even babies that are taken into care at birth (like mine) will take nearly a year to get through the system, resulting in them being moved between two or three mother figures before they are even one year old, and risking all kinds of attachment disorders and other difficulties. I am a great fan of adoption - it has given me a beautiful daughter - but I do not kid myself that it is an ideal start in life; my dd has already gone through more trauma and loss in her first year of life than I want to think about.
There is also very good research evidence showing the lifelong impact on birth mothers of giving their children up for adoption. Many suffer terrible trauma. Far more than those who suffer trauma after abortion. That may not be a popular argument with many posters, but it is backed by evidence.
The third issue with adoption is that so many birth mothers don't go through with it (particularly the very young ones). I have a close family member who got pregnant very young, and decided to give the baby up for adoption. She didn't - she saw the baby, found him very cute, and decided to keep him. Now, in many cases that would turn out to be a happy ending. Not in this case, or in many others I suspect. She ended up basically abandoning and neglecting the child, who then had to be raised by other family members. He didn't get a new start with adoptive parents who adored him; he got shunted from pillar to post with the clear understanding that his mum didn't actually want him.
This DOESN'T mean that I think women shouldn't choose adoption over abortion. It can be absolutely the right choice, and I think it's probably true that it is not given due airtime as an option by professionals guiding women through unplanned pregnancy. But I do think it's a difficult, complex, challenging option, and I hate the way it comes up in these debates as, "If you don't want the child, why not give it to someone who does?" It's nowhere near as simple as that.