Brother and Sister by Joanna Trollope

Trollope is the author of seventeen novels and I believe this is the first I have read....at least I don't recall reading any others. I enjoyed the book a lot and like her writing which is thoughtful, but easy to read.
The novel tells the story of Nathalie and David, two siblings who were both adopted by the same parents. They are in their mid to late thirties and have never sought to find their birth mother, until now. Nathalie, the mother of a five year old, Polly, who is about to have minor surgery, begins to wonder about her birth mother because the surgery raises questions about her daughter's genetic make-up.
Nathalie and David have a strong bond even though they are not blood related. Their relationship is complex and causes some problems with their spouses; they tend to go to each other for "deep" issues and problems.
As a matter of fact, Nathalie first tells David that she is going to look for her birth mother before even telling her common law husband, Steve.  She even insists that David look for his birth mother, too.
The issues that are raised were very interesting to me and quite compelling. If one is not adopted, it's not a topic that would necessarily cross one's mind. But this novel was quite realistic in dealing with the issues - the loyalties, insecurities, doubt.
It was an engaging read and I am going to read more Trollope novels, I am sure.