Offenses of Sexual nature are taken very seriously and CIC is very likely to refuse sponsorship by people convicted for such offenses. Consult a Good Lawyer.
You may not be eligible to be a sponsor if you:
-did not meet the terms of a sponsorship agreement in the past,
-did not pay alimony or child support even though a court ordered it,
-get government financial help for reasons other than being disabled,
were convicted of
-an offence of a sexual nature,
-a violent crime,
-an offence against a relative that resulted in bodily harm or
-an attempt or threat to commit any such offences, depending on the detailss of the case, such as
--the type of offence,
--how long ago it occurred and
--whether a record suspension was issued (see Sponsorship bar for violent crime below),
-were sponsored as a spouse, common-law or conjugal partner in the past and became a permanent resident of Canada less than five years ago (see Five-year sponsorship bar below)
-did not pay back an immigration loan, made late payments or missed payments,
-are in prison or
-have declared bankruptcy and have not been released from it yet.
-Other things not on this list may stop you from being able to sponsor a relative.
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Sponsorship bar for violent crime
The sponsorship bar stops people who have been convicted of certain crimes from sponsoring a family member.
If you have been convicted of a crime that caused bodily harm to any of the relatives below, you cannot sponsor anyone under the Family Class.
Note:
-“Partner” includes common-law and conjugal partners.
-Relatives not listed here may still fall under this category. If you are not sure, check the full list of rules or contact the office processing your application.
-Relatives the sponsorship bar can apply to:
-your current or ex-spouse/partner and/or their children,
-your children,
-your parent/grandparent, child/grandchild, sibling, niece/nephew, aunt/uncle, or cousin, or
-the current or ex-spouse/partner and children of the above
-the parent/grandparent, child/grandchild, sibling, niece/nephew, aunt/uncle, or cousin of your current or ex-spouse/partner or children, or
-the current or ex-spouse/partner and children of any of the above
-your child's spouse, partner or children,
-your spouse's, partner's or child's ex-spouse or ex-partner and children,
-your partner's parent/grandparent, child/grandchild, sibling, niece/nephew, aunt/uncle, or cousin, or
-the current or ex-spouse/partner (and their children)of any of the above,
-a foster child who is or was cared for by you,
-your current or ex-spouse/partner or their children,
-your parent/grandparent, child/grandchild, sibling, aunt/uncle or cousin, or
-the current or ex-spouse/partner (and their children) of any of the above, or
-your current or ex-boyfriend/girlfriend, their spouse or common-law partner, and their dependent children.
Source: http://www.cic.gc.ca/english/immigrate/sponsor/spouse-apply-who.asp