['We investigated parent-of-origin and allele-specific expression effects on obesity and hepatic gene expression in reciprocal crosses between the Berlin Fat Mouse Inbred line (BFMI) and C57Bl/6NCrl (B6N).', 'We found that F1-males with a BFMI mother developed 1.8 times more fat mass on a high fat diet at 10 weeks than F1-males of a BFMI father. The phenotype was detectable from six weeks on and was preserved after cross-fostering. RNA-seq data of liver provided evidence for higher biosynthesis and elongation of fatty acids (p\u2009=\u20090.00635) in obese male offspring of a BFMI mother versus lean offspring of a BFMI father. Furthermore, fatty acid degradation (p\u2009=\u20090.00198) and the peroxisome pathway were impaired (p\u2009=\u20090.00094). The circadian rhythm was affected as well (p\u2009=\u20090.00087). Among the highest up-regulated protein coding genes in obese males were Acot4 (1.82 fold, p\u2009=\u20090.022), Cyp4a10 (1.35 fold, p\u2009=\u20090.026) and Cyp4a14 (1.32 fold, p\u2009=\u20090.012), which hydroxylize fatty acids and which are known to be increased in liver steatosis. Obese males showed lower expression of the genetically imprinted and paternally expressed 3 (Peg3) gene (0.31 fold, p\u2009=\u20090.046) and higher expression of the androgen receptor (Ar) gene (2.38 fold, p\u2009=\u20090.068). Allelic imbalance was found for expression of ATP-binding cassette transporter gene Abca8b. Several of the differentially expressed genes contain estrogen response elements.'] Does the direction of cross affect [ corrected ] obesity after puberty in male but not female offspring?