A few days later I watched it with my mum in the dubbed into English version and when that moment came up, Lola instead says "I belong to him". Which after the film ended my mum said made it seem to her that perhaps Lola's real father was this minor security guard character rather than the colder, adulterous banker father! It was fascinating to me that just changing a sentence threw a whole new angle on the film that I'd not considered in the viewing of the film in its subtitled version. And listening to Tykwer's audio commentary didn't throw much light on it, as during that scene he just says that: "There an invisible line between them that is disturbing without explaining it"!
Whether he's actually Lola's father or not is ambiguous (and really not present at all in the German version, where it seems more about the 'miracle'), but that was a fun moment of learning about the nuances of translation!
Its also interesting in building up that security guard character's role into quite a major one by implication, considering he (literally!) kicks off the film in the pre-credits sequence, and tails the diverging timelines together with the ambulance scene at the end.