Adolescents need safe effective drugs that have undergone ethically approved testing in clinical trials; such studies often require pregnancy testing in ‘women of childbearing age’ which includes children/adolescents. There is a lack of consistent standard operating procedures for pregnancy testing in these individuals, in either research or clinical (ie, both preprocedure and clinical emergency) settings. Some harmonisation between a selective or universal testing approach based on a risk analysis of the trial drug or procedure would seem sensible. The need for pregnancy testing and the reasons for the method chosen (universal or selective) should be clearly defined in the research protocol. Research ethics committees (RECs) need to satisfy themselves that the selection of subjects to be tested, the procedures for obtaining consent and the respecting of the young person's confidentiality are appropriate and that management of any positive tests are in accord with local safeguarding policies and procedures. Researchers should have core competencies necessary to manage sensitive questioning and child safeguarding training. Clinical trials of medicinal product (CTIMP) pregnancy testing in females 13–15 years of age requires parental consent and the child's active involvement in the decision-making process (‘assent’) the implications of a positive test should be discussed in advance. Children under 13 years should not normally be subject to pregnancy testing in CTIMPs, unless there are exceptional circumstances, for example, a trial of contraceptive agents of a high teratogenicity risk, as reviewed by a specialist paediatric REC. We analyse the ethical, legal and practical aspects of this issues and supply guidance to support those involved.