Background: Vertical transmission of HIV infection can occur during pregnancy, during childbirth or through breastfeeding. The recommendations issued by the various international guidelines (WHO 2010, EACS 2017, DHHS 2017) on the safety of breastfeeding of HIV-infected women in effective antiretroviral treatment do not provide univocal indications referring to individual countries the choice to advise or advise against such procedure. Methods: A retrospective study was conducted in a small cohort of HIV-infected pregnant women who, despite the information received, decided to breastfeed their children. The observation was carried out in the period between March 2017 and June 2021. In all newborns, prophylaxis therapy was initiated at birth, according to the treatment guidelines, the scheme adopted involved the administration of zidovudine (AZT) orally for 4 weeks, started immediately after the childbirth. Breastfeeding time was, on average, 5 months. Results: No contagion was diagnosed. All infants were tested for HIV-RNA at birth, 1, 3, and 6 months after birth, and 1, 3 and 3 months after stopping breastfeeding. Conclusions: The data obtained represent, in our opinion, a solicitation to discuss and re-evaluate scientific evidence that starting from "Undetectable Equals Untransmittable" (U = U) can open a scientific and cultural review of breastfeeding.