Can a sperm cell with abnormal morphology like having two heads or two tails fertilise an egg cell? If it can is the fetus normal? Can it survive the pregnancy? Thanks, Jo

Theoretically it might be possible but in practise occurs rarely. As you rightly say, if that did occur there would be a high likelihood that the foetus would be damaged and/or malformed. If that was the case then the likely outcome would be a miscarriage. So the short answer to your question is yes it is possible that a damaged sperm might result in a baby with abnormalities, but thankfully it is rare. Nature is very good at minimising these situations – another good example of “the survival of the fittest”.