Battle of the sex chromosomes: How competition affects X vs. Y sperm fitness / Octopuses have some of the oldest known sex chromosomes, study finds / Echidna genome study unravels the events leading to multiple sex chromosomes / Imane Khelif failed gender eligibility test due to chromosomes, says IBA / Sex chromosomes may reduce 'sexual conflict' during evolution, say researchers / XX and XY chromosome: What are differences in sex development? / Platypus and chicken reveal how chromosomes balance between the sexes / Biden judicial nominee can't say whether chromosomes determine sex: 'I have never studied biology' / Earliest known sex chromosomes evolved in octopuses / Sex chromosomes responsible for much more than determining sex, study shows