Snopes doubts that this is true -
As far as we can tell, this recent version of the story originated in the 18 May 2004 edition of the UK newspaper The Mirror and was picked up from there by other news sources, including UPI. The article looks to be either a spoof or a hoax ?- the type of story one would expect to find in a supermarket tabloid ?- not only because it repeats a common urban legend motif, but also because:
It has a lack of detail common to tabloid or spoof articles: The couple is identified only as a "husband" and a "wife" (with no quotes from either), and no name or title is provided for the article's single source of information, a university representative (he's merely an unnamed "spokesman").
The spokesman states that it was only after the couple "were subjected to a battery of tests and both were found to be perfectly fertile that we asked them how often they had sex." In-depth questions about frequency and nature of sexual activity are generally asked of couples well before any actual fertility testing is undertaken, in part for this very reason (i.e., nobody wants to run a battery of expensive tests only to find out that some external factor was responsible for the couple's failure to conceive ?- like maybe the couple is engaging in sex infrequently, and always at a time when the woman is probably not ovulating.)
The article includes some way over-the-top, buffoonish statements (ones not befitting a medical professional) based upon information supplied by the putative spokesman, such as: "We're not talking about retards here, but a couple who were brought up in a strict religious environment" and "The couple had read up about in-vitro fertilisation treatment but believed it was something to do with a 'turkey baster, a mattress and a woman standing on her head.'" (Would a couple so ignorant of the basics of sex and pregnancy really understand the concept of IVF?)
No one we contacted at Lübeck University (at least, no English-speaking personnel ?- my command of German is nicht so gut) had any knowledge of this story
The Mirror hasn't responded to our inquiries yet, but we'd be quite surprised if this report turned out to be anything but a fictional bit of humor.
http://www.snopes.com/pregnant/nosex.asp