A child born in 1968 could certainly still be living and one or both of her parents could be as well.
Searching on FreeBMD for births in 1968 with father Jones & mother Lewis brings up over 40 female births. There could also be children born late 1968 registered in the Jan./Mar. quarter of 1969.
However, we don't know from your post if the parents were married at the time of the child's birth - in which case the birth likely indexed under Lewis (mother's name) unless father attended to registration to confirm he was the father.
Billinge Hospital, in 1968, came under Ince registration district according to FreeBMD.
https://www.ukbmd.org.uk/reg/districts/ince.htmlNarrowing down the 1968 births on FreeBMD to Ince district brings up one female birth. HOWEVER, the birth may have been registered in the district where the parents lived. Only by ordering the Ince certificate will you know who the parents were.