I have just became a step parent in Alberta Canada. My wife…

Since your spouse already has joint custody of your stepdaughter with her former spouse, you cannot have joint custody.

Your stepdaughter is not treated as an adult until she is 18.

You may want to meet with a family law lawyer to prepare a will and power of attorney forms that names you as a legal guardian of your stepdaughter. There is nothing else you can do to change the custody status.

Your province or territory's lawyer referral service can provide you with the names of local lawyers who can act on your behalf.

I now see that you would prefer to work with another expert. I will opt out of this question.

As they were never married and your stepdaughter has not lived with her for more than 1-year, your spouse has sole guardianship (custody) of your stepdaughter.

But even if you adopt your stepdaughter, the biological parent would still have parental rights until she was 18.

You could complete an application to adopt your stepdaughter through the provisions of Alberta's Child Youth and Family Enhancement Act. I suggest that you retain a family law lawyer to assist you with this process.

You would have full rights as an adoptive parents. The biological parent would still have certain rights too-like access and the right to receive information about her health education and well-being.

You should review the terms of the adoption with an Alberta family law lawyer.

If the biological father's consent was needed, it is possible that he could claim to be a joint guardian and object. This would mean that your spouse would need to litigate the issue of guardianship first.

By the time, this would be resolved, it is possible that your stepdaugher would be 18 already.

This is why I gave you the power of attorney and will suggestions before. Most people in your circumstances would not adopt and just become a stepparent.

The power of attorney option involves you stepping into your spouse's "shoes" for decisionmaking regarding care or property when she is incapacitated-it would not cover all situations when your spouse was not around and your stepdaughter needed urgent medical care. Only her mother could sign. Yet, as a minor your stepdaugher would still receive urgent medical treatment if it was needed in an emergency situation even if you couldn't sign the forms.