Is a convert who is a hemophiliac required to have a circumcision, if it could result in his bleeding to death?
I will answer this question in a theoretical sense. Before making any real-life decisions on the matter, you would need to present the details of the particular case before rabbinic and medical authorities who will evaluate each case individually.
This issue is discussed by many great halachic authorities, concerning prospective converts suffering from any of a number of ailments which preclude safe circumcision.
The consensus is that, unfortunately, such an individual cannot convert. The halachically described procedure for a male’s conversion must include circumcision. Since in this instance there is a danger involved in the circumcision, this person cannot convert.
In fact, even if he would wish to convert at his own risk, the Jewish court would not allow him to risk his life in order to become Jewish. Becoming Jewish is great, but staying alive is more important . . .
I would like to remind you that according to Jewish belief, a non-Jew need not convert to Judaism in order to achieve spiritual fulfillment. (See The Discovery of Planet Earth.)
Rabbi Menachem Posner
P.S. Needless to say, the above only applies to a non-Jew who wishes to convert. However, a Jewish child who cannot be circumcised due to medical reasons does not lose his Jewish status or identity.