For people who uphold the morality of sticking to one partner only, making sure if the child is his will not be a problem at all. Some take pride, though, for being able to being romantically and even just physically involved with other women and when some of them say they are pregnant and it is your baby, how can you be so sure? On the part of the woman, if she has been faithful to just one man, she is quite sure but of course doubts can cloud your senses. To be sure, you just need a paternity testing kit and you will know if the child shares your DNA.