In most countries, there are now proportionately more female than male science graduates under the age of 30. Yet, women remain underrepresented in tenured positions and in decision-making bodies that are concerned with scientific issues. Why has the representation of women at the earlier phases of a scientific career increased? How has the position of women changed? Is it just a matter of time until more women get to the top? And, importantly, do women want the top jobs? On page 287, Fiona M. Watt discusses how the situation has changed over the past 30 years, which issues remain and how to compete to make it to the top.

For men, competition is also hard, especially at the biological level. Until recently, it was thought that following ejaculation into the female genital tract in mammals, large numbers of spermatozoa raced towards the egg, and competed to fertilize it. This 'competitive-race model' was dismantled when it was shown that, in fact, only a few of the ejaculated spermatozoa — only ∼1 in every million spermatozoa in humans — enter the Fallopian tubes. Michael Eisenbach and Laura G. Giojalas (page 276) discuss the mechanisms by which mammalian sperm might be guided to make their long, obstructed way to the egg.

Moving from fertilization to embryology, a short Timeline article (page 296) presents the status of experimental embryology, a field that was at the forefront of biological research a century ago. In this month's article from our Article Series on Developmental Cell Biology (http://www.nature.com/nrm/series/devcellbiol), Edward M. De Robertis recounts the story of the birth, decline and revival of amphibian experimental embryology, and discusses the recent studies that have uncovered a molecular pathway that explains how embryonic self-regulation works.