Abstract Purpose Inadvertent and/or unknowing exposure to drugs and drug residues has been frequently debated in situations of so-called adverse analytical finding (AAF) in the context of sports drug testing programs. Transfer of drug residues via unprotected intercourse is a conceivable scenario but scientific data and authentic case reports are scarce. Herein, investigations into two AAFs with the peroxisome proliferator-activated receptor delta (PPARδ) agonist GW1516 are reported and discussed. Methods To probe for a contamination scenario involving sexual intercourse, two assays were used to determine semenogelin in human urine, with one employing an immunochromatographic lateral flow approach and another based on liquid chromatography–tandem mass spectrometry. Further, drug-residue testing using patients’ ejaculate was conducted by utilizing liquid chromatography in conjunction with a triple quadrupole mass spectrometer, followed by re-analysis of suspect samples (i.e., samples indicating the presence of relevant compounds) using high resolution/high mass accuracy mass spectrometry. Results In one case, but not the other, the possibility of intimate contact as the source of the AAF was confirmed after a thorough investigation of potential contamination scenarios. Subsequent research revealed analytical evidence for the presence of seminal fluid in one of the female athlete’s doping control urine samples, and the analysis of clinical ejaculate specimens provided first data on an authentic concentration level of GW1516 and its metabolites in human seminal fluid. Conclusions The combined facts substantiate the possibility of an AAF caused by unprotected sexual intercourse and the plausibility of the case-related arguments.