Fourth: Circumcision.
Article 185
Tawaf of an uncircumcised man is not correct and an obligatory precaution is that children should be also circumcised for performing Tawaf.
Article 186
Whenever a person performs Tawaf without circumcision, deliberately or because of ignorance or forgetfulness, then his Tawaf is invalidated.
Article 187
Whenever an adult has not been circumcised and gains the ability of performing Hajj (like people who are newly converted), should perform Hajj in that year if he can be circumcised. But if he cannot do it, then he should delay his Hajj until he is circumcised, and if circumcision is harmful for him, then he should perform Hajj in that condition (but it is Mustahab precaution to take a proxy for performing Tawaf in behalf of him adding to his own Tawaf).