My son got his girlfriends pregnant. I need some advice.

Last month I found out that I am going to be a granddad at 36 but lets go back to the beginning. I've been rising my son on my own since he was just under one year old. That is after his mother announced that she's too young for this shit and decided that she must have some fun in life. She tried to make a great comeback few years later when he was 5 or 6 but the doors were already closed for good. So she's not in the picture or anywhere near it. My son who is now 15, for past 6 months has been dating two young ladies from his new school. Girl A who is 16 and girl B who is 15. Both young ladies not only know about each other but say that all three of them are in deeply love with each other and plan their future together, etc. etc.. Both of them were often visiting and staying over in our house when I was away working. I had very serious chat with my son about birds and bees after I found that he's sexually active and he promised me that he'll make sure that they always use protection and don't do anything stupid. He clearly didn't keep his promise as last month he told me that girl A is pregnant. These things happen but it could have been avoided, I try to be understanding and support both of them. Her parents after initially being very upset, accepted the fact that she wants to keep the child and started supporting her. We met few times since then and had a very constructive conversation about our children's future. My son wants to be involved all along. He has completely changed since. He's reading lots parenting books and asks questions about rising a child. I know that they tried to get some advice online from young people who became parents at similar age as they are. So far so good but A's parents don't know about girl B yet. Well, I found out about her just yesterday. For some time I thought that B is no longer involved as she stopped coming and rarely heard them talking despite of living almost next door to us. This changed on Sunday when I returned from work a bit earlier than originally planned and as I was minding my own business downstairs I heard that B was upstairs with my son talking about naming THEIR CHILD. So a child B is also expecting my son's child. After confronting them, he and the young lady admitted that they not only never used any kind of contraception but all three of them planned to get pregnant and to have babies at the same time. I still try to understand their actions and what exactly they tried to achieve. I just can't accept the explanation two of them gave. I want to have very serious chat with all three of them soon as possible to find out what exactly they are planning and what are their expectations, how and why the hell it happened. No A's or B's parents would be present. I briefly spoke to B already and she doesn't want her parents to know about it just yet. I can understand her on that as describing her parents as nice neighbours and good parents would be a huge understatement. As for my son I seriously think that he should get his bollocks chopped off with two blunt bricks as a precaution for future. I still believe that he is mature enough to understand the consequences and how serious this is going to get. I try to be as reasonable as possible but for the first time I have no clue how to deal with this situation. I was 20 when he was born and the only help I ever received when his mother left was the advice to put him for adoption so I am not going to abandon him and in the same way I don't want him to run away from the responsibility of rising a child or abandoning their mother (mothers) no matter how idiotic what he allowed to happen looks. via /r/Parenting https://ift.tt/2KMrOpV