Praise be to Allah.
Thank you for submitting this question, because the issue of circumcision is one of the issues which in several cases forms a barrier for some of those who want to enter the religion of Islam.
The matter is easier than many people think. As for (male) circumcision, it is one of the symbols of Islam, is part of sound human nature (fitrah), and is part of the way of Ibraaheem (peace be upon him). Allah, may He be exalted, says (interpretation of the meaning): “Then We revealed to you, [O Muhammad], to follow the religion of Abraham, inclining toward truth” [an-Nahl 16:123]. And the Prophet (blessings and peace of Allah be upon him) said: “Ibraaheem the Prophet (peace be upon him) circumcised himself when he was eighty years old…” Narrated by al-Bukhaari (6/388).
Circumcision is obligatory for a Muslim man, if he is able to do it. If he is not able to do it, such as if he fears that he may die if he is circumcised, or if a trustworthy doctor has told him that it will lead to haemorrhaging that may cause his death, then he is exempt from circumcision in that case, and he is not sinning if he does not do it.
But it is not appropriate under any circumstances to let the issue of circumcision be a barrier that prevents a person from entering the faith; rather the soundness of a person’s Islam does not depend upon him being circumcised. A person’s entering the religion of Islam is valid even if he does not get circumcised.
With regard to the issue of female circumcision, you will find the answer in question no. 427 .
I ask Allah to enable you to do all that is good and to protect you from all that is evil.
Blessings and peace be upon our Prophet Muhammad.