This work was supported by the Spanish Ministry of Science and Innovation -MICINN– (AGL2009-10059). MM, EC and BT are supported by MICINN-RYC08-03454, MEC-FPU-AP2009-5265 and Cajastur, respectively. E.S. is supported by Award R01HD059909 from the National Institute of Health (NIH), USA. The authors are members of the COST Action FA1201 Epiconcept: Epigenetics and Periconception environment.