Human chromosomes during metaphase. Credit: Steffen Dietzel/Wikipedia © 2017 Phys.org More information: “A father effect explains sex-ratio bias,” Proceedings of the Royal Society B (2017). DOI: 10.1098/rspb.2017.1159 This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.