at 7 or 8 weeks this woman said her babies were 9 and 10 centimeter.... isn´t that kind of big? Let´s say it´s 8 or 9 weeks, 9 and 10 centimeter for twins...

Are you sure she didn´t say millimetres rather than centimetres? That sounds more like 7th week size...

The only way to fully be sure he is the father is to wait till the birth and do a DNA test and i would not say anything to him.

i would not say to him "you are not the father" ...i would say "make sure to do a dna test, and don´t commit to anything until you do"

 People always say things about each other, and they are not always correct... and even with your warning you might cause a lot of trouble...  He won´t be able to have a DNA test until the babies are born, and it will really consume him, not to know whether he is the father or not.

Let´s say, the friend is correct and you told him, he will thank you forever, but what if not???

The unborn babies will loose their father forever!!! I don´t think it is such a good idea.

By the way, why do you always say babies?  Are they twins?  And the if the babies were concepted in September, then they must be definitely more than 6 weeks by now.. as like somebody else said, pregnancy is calculated from the first day of last period.. so you have to at least add 2 weeks to your calculations, which will reach 8 weeks, and it should be normal then.. And if she is carrying twins, definitely her tummy will be bigger than a single baby´s mum.

They are twins... The babies are the result of a one night stand, but he has recently started to "date" this girl or something, only because of the babies.

I want to make sure he doesn´t take things to far. What I mean is, he´s the kind of guy who would marry this girl, just to make sure they won´t be ´bastard´ children. If this decision would be based on a lie, he would be in a marriage based on a lie. For this, I´m concerned.

If I thought he was just goofing around, and the truth would come out somehow, and yes, it would mess up his life for a few months, I wouldn´t be bothered with it Teaches a guy to use protection However, if I think this can mess up his entire life...what do I do then...

Anyway, I have read your ideas about it, and I´m contemplating Because of the Turkish translation (thank you!) I now know his sort of friend told me I must tell him, although you also have compelling points not to.