This paper considers whether section 20 of the Offences Against the Person Act 1861, which has been used to prosecute those who transmit the HIV virus in sexual relationships (eg, R v Konzani), could be used to prosecute women (in England and Wales) who transmit the virus to their child during pregnancy, delivery or via breast feeding. The discussion concludes that prosecution for transmission in pregnancy/delivery is unlikely. However, it is argued that there might be scope to prosecute the transmission of the virus via breast feeding in the event that there was sufficient evidence. However, this would also be subject to the Crown Prosecution Service deeming such a prosecution to be in the public interest. The paper does not seek to examine the ethical issues involved. However, it acknowledges that this issue is part of a broader debate as to whether, and if so, when, it is appropriate to criminalise the transmission of disease. © 2014 by the BMJ Publishing Group Ltd & Institute of Medical Ethics.