On 24 March each year, Ada Lovelace Day is celebrated by an international day of blogging to highlight the achievements of women in technology and science. Ada Lovelace (1815–1852) was the daughter of the poet Lord Byron, but her enduring claim to fame is as the world's first computer programmer. She worked on Charles Babbage's early mechanical general-purpose computer, the analytical engine, and is credited with writing the first computer program. Hundreds of women were lauded in cyberspace this year, but some of the most honored names caught our eye. Three of the most blogged-about women were molecular biologists: Rosalind Franklin, Barbara McClintock and Dorothy Crowfoot Hodgkin.

The inclusion of Franklin, McClintock and Crowfoot Hodgkin reflects not only their outstanding scientific achievements but also the assimilation of their work into popular culture. All three have biographies of their lives gracing bookshelves, and Franklin's role in the discovery of the structure of DNA was the subject of the film DNA's Dark Lady. But the books about these three women's lives illustrate just how difficult it was to succeed as a female scientist. Biographers of Franklin and McClintock suggest that both were unfairly treated, and these books are central texts for many women-in-science studies. The biography of Crowfoot Hodgkin, Dorothy Hodgkin: A Life, is different. It's a tale of balancing a passion for science with bringing up children and taking an active interest in international politics.

Reading the biography of Crowfoot Hodgkin, the supportive role played by Somerville College, at the University of Oxford, stands out. Crowfoot Hodgkin was the first fellow to become pregnant while holding a fellowship, but the college responded in an enlightened manner, and she became the first woman at University of Oxford to receive paid maternity leave. This was 33 years before the university as a whole adopted this policy and 37 years before statutory maternity pay became law in the UK in 1975. Through the support of her family and the college, Crowfoot Hodgkin was able to continue working during her pregnancy and while bringing up young children. The benefits to the college and to science in general have handsomely rewarded this support.

Incredibly, more than 40 years later, many women—and men too—find themselves in a less supportive environment than that of Crowfoot Hodgkin at prewar Somerville College. Many women and men give up their careers when they have children, partly because it is difficult to cope with the demands of the long hours needed in the laboratory and partly because of the expense of childcare. With two children in daycare, many find that it is cheaper to stay at home. Others understandably want to spend time with their young children.

Career breaks are not always a matter of personal choice. As the economies of the US and Europe recover from recession, many scientists may find themselves forced to look for jobs elsewhere following redundancy, but many will want to return. And caregiving is not just about looking after children but increasingly involves caring for elderly parents, and with aging populations, this is a commitment we are likely to see more and more.

But such a break comes at a huge cost, not only to the individual but to science and to the economy. After a break, women usually lose their place on the career ladder, preventing them from reaching senior positions. The UK Resource Centre for Women in Science, Engineering and Technology (UKRC) estimates that the cost to the UK of women scientists and engineers working below their level of qualification, being unemployed or otherwise inactive in this sector is £2 billion.

But there are reasons to be hopeful. For people wanting to take only a short break and return to their old job, funding bodies are beginning to build this into their structure. The legislation entitled 'Fulfilling the Potential of Women in Academic Science and Engineering' that has just passed through the US House of Representatives, which mandates that federal funding agencies build in extensions for caregivers, is an encouraging sign. Similar initiatives are now being phased in across the European Union.

Other positive initiatives are also welcome. The UKRC has worked with the Open University in the UK to develop a short 10-week course for anyone who has worked in or studied science and engineering to analyze the opportunities in this sector and develop a plan for returning to work.

The UK Institute of Physics has a booklet that is free to download from its website entitled Best Practice in Career-Break Management. Their guidance shows that planning ahead is the key to a successful return, whether one is taking a short break and returning to the same job or the intention is to take a break for several years. Their advice includes retaining membership of professional institutions or bodies and using this as a way of maintaining professional networks. Finding a mentor can help enormously, as can joining a university library, which in the UK are often open to the public, providing access to scientific journals. Other options are to attend scientific conferences (some society conferences are reasonably priced) or to tutor for adult education courses or for the Open University. A Nature Podcast entitled “Career Breaks for Women” (http://www.nature.com/naturejobs/career-toolkit/podcasts/archive/index.html) on the subject might also prompt some ideas.

Returners need accessible, relevant advice on science and engineering and a supportive environment, as well as a fair chance to be employed. It is impossible to predict whether the scientist juggling so many commitments will one day win the Nobel Prize.