Ref. 25:
This reference (in English) is the report by Bearman-Bruckner that also thoroughly debunked the (by now infamous) Bailey-Pillard study (ref.23), something that one of the two researchers even later admitted. Pillard – a homosexual himself – had recruited his sample objects (in the ref. 23 study) through advertisement in homosexual publications and thereby intentionally biased the results. Their criticism of the Bailey-Pillard study (translated into your language) reads (from page 12 of report; 3rd paragraph):
Substantially higher concordance for homosexual orientation has been reported in previous research. We believe that previous work is largely incorrect as a result of reliance on non-representative samples from, for example, readers of gay publications, and reliance on indirect evidence.
For a look at the original text in English click here (file size:152 k)