Caroline Criado Perez in The Guardian

In a characteristically clear-eyed piece for The Guardian, feminist speaker and author Caroline Criado Perez returns to one of the central arguments of her landmark book Invisible Women: that the failure to adequately represent women in clinical trials is not a bureaucratic oversight — it is a life-threatening one.

The immediate prompt for the article is a significant, if overdue, admission from the UK's Medicines and Healthcare products Regulatory Agency. For the first time, the MHRA has identified a notable imbalance in trials conducted between 2019 and 2023, finding that nearly twice as many all-male trials were conducted as all-female ones. Criado Perez welcomes the acknowledgement, while making clear that recognition alone is far from sufficient.

When she first examined the clinical trial landscape in 2018, the UK stood out as an outlier, and not in a good way. Unlike the EU, the US, Canada, and Australia, the UK had no funding requirements, no approval requirements, and collected no data whatsoever to track the problem. Progress, in other words, has been slow — and the cost has been borne overwhelmingly by women.

She also highlights a subtler problem: while 90% of trials included both sexes, inclusion alone does not guarantee that researchers will consider or analyse differences between them. A mixed-sex trial that treats male data as the default is, in practice, little better than an all-male one.

The MHRA's analysis, Criado Perez concludes, has not been done well — but she remains glad that it has been done at all. It is a measured response from a writer who understands that in this field, imperfect progress still represents progress.