For those who are interested, I got a reply from the BBC:
Dear Mr Wilson
Thank you for your e-mail.
You are quite correct to point out that this advert is not appropriate for the BBC and I have asked Google to remove it immediately. We are working closely with Google to ensure that their third party supplied adverts meet our standards. I'm happy to say that instances such as this are rare and decreasing. I am very grateful to you for bringing it to our attention.
Thanks again for taking the time to contact us.
Liam Boyle BBC.COM Support Team
I am on holiday in France. While reading the following article, I found an advert for homophobic content that I do not believe to be consistent with the BBC's role. This is the article I was reading:
In the Google text adverts at the bottom, one was labelled "Homosexuality at Home / How should christians respond to homosexuality within the family? ChristianityToday.com/marriage/" and linked to this page:
I do not consider saving a fraction on the license fee to be justification to promote homophobic content like this. I believe that Christians have a right to believe that homosexuality is sinful, but the BBC has no business helping them promote that destructive message. I consider this message to be inconsistent with the BBC's first public purposes of "sustaining citizenship and civil society".