If I had an 'encounter' albeit very brief indeed & the man did not ejaculate on 10 Dec 2011 then had a normal period on 24 Dec 2011 was then reunited with my partner on 31 Dec 2011 & had sex then & on 1 Jan then on 5 Jan had what I suspected were implantation pains began to feel sick 3-4 weeks later & gave birth on 30 Sep 2012 is there any doubt over paternity or is that ridiculous? Thanks

You had sex... therefore you can get pregnant. He doesn't HAVE to ejaculate to get the job done.

You had sex with more than one man in that one month window... thus you need to have DNA testing done to know who it was.