Can a former same-sex partner who was not a legal parent seek recognition after the relationship ends?

It depends on the facts, but it isn't automatic — being someone's partner and being involved in a child's life is not, by itself, the same as being a legal parent under Ontario's rules, which generally require either a genetic connection, being the birth parent, or meeting the specific requirements of the assisted reproduction and parentage framework, such as being party to a qualifying pre-conception agreement or being the birth parent's spouse or partner at the relevant time. A former partner who was never recognized as a legal parent under one of these routes may be able to apply to court for a declaration of parentage if the facts support it — for example, if there was a clear, documented intention at the time of conception that they would be a parent, even if the formal paperwork was incomplete.

Where parentage genuinely cannot be established, a former partner without legal parent status may still be able to pursue a contact order to maintain a relationship with the child, a different and lower threshold than seeking parentage. Anyone in this situation should get legal advice promptly, since evidence of intentions at the time of conception tends to matter more the sooner it's gathered.