Serena had "enormous, unforgiving breasts" which she covered with a cardigan. (PROSE: I Am a Dalek) Breast implants were composed of plastic. (TV: Rose) "Boobs" was a slang term for breasts. (AUDIO: The Veiled Leopard)
Behind the scenes Edit
The parodic Comic Relief story The Curse of Fatal Death had its version of the Master outfitted with "Dalek bumps", identified as etheric beam locators, which are placed in such a way that they appear to give the Master "breasts".
When the Ninth Doctor makes note of his "breasts", the Master insists that they're bumps, though he suggestively tells Emma that they are "extremely firm". After regenerating, the Tenth Doctor calls the Master "camp" and mockingly compliments him on his "nice tits", while the Eleventh Doctor believes the Master to be a girl. Finally, after regenerating into female form, the Thirteenth Doctor believes she has etheric beam locators, even pointing out an "on switch", leading Emma to inform her that they are actual breasts.