Ending romantic relationship bcos of incompatibility in genotype is best choice ever, Love is suppose to be a beautiful things, now testing the weight of love by bringing in worries and problems is not advised at all, just like when God told us that even when He watches over us , we should also be careful, tell me someone testing the power of God's protection by playing with petrol and fire, will God protection cover him?? So ,it's just a typical example of bringing a child that will be in pain for the years he will use on earth and putting you both the couple in problem.

Once you already in talking stage, it is very important to ask genotype before anyone falls deeper in love .
Well, another thing that's possible is if they agreed on not birthing but I see that as selfishness, God said we should multiply, everyone will see their compability, so everyone should go for someone that they are both compatible