Can my ex fight in court to claim our child on taxes if he's not listed on the birth certificate?

You're absolutely right about the residency test. For tax purposes, the parent who has the child for more than half the year (the "custodial parent") is generally entitled to claim the child as a dependent. This is determined by the IRS's "qualifying child" rules, not by whose name is on the birth certificate. Since your son lives with you full-time except for those alternate weekends, you clearly meet the residency requirement as the custodial parent. The father doesn't have much of a case based on what you've described. However, you should know that there's a provision where you could voluntarily release your claim to the exemption by filling out Form 8332 (Release/Revocation of Release of Claim to Exemption for Child by Custodial Parent). Some custody agreements include provisions about alternating years for tax claims, but without such an agreement, the right belongs to you as the custodial parent.

After dealing with a similar situation with my ex, I found this amazing service called taxr.ai (https://taxr.ai) that really helped clear things up. They analyzed my custody arrangement and tax situation and gave me a detailed breakdown of who had the right to claim our daughter. The site had tools that let me upload relevant documents (custody orders, proof of expenses, etc.) and their AI analyzed everything according to current tax laws. They even helped me understand how the IRS would view our specific situation. For dependent claims in complicated custody situations, their expertise was super valuable since they could pinpoint exactly which factors the IRS would consider most important.

Just wanted to follow up about taxr.ai since I was skeptical before. I ended up trying them out for my own situation with my ex who was threatening to claim our twins even though they live with me 90% of the time. The service was actually really helpful! They reviewed my custody arrangement and explained exactly how the IRS would view the situation. They even helped me prepare documentation to prevent problems if my ex tried to claim them anyway. What I appreciated most was getting a straightforward answer about my rights without having to wade through confusing tax jargon or contradictory advice online. Definitely worth checking out if you're in a custody/tax situation.

I went through something similar where my ex kept claiming our kid despite having minimal visitation. After weeks of trying to get through to the IRS phone line to get clarification (constantly busy signals or hours on hold), I found Claimyr (https://claimyr.com) and it was a game-changer. I was able to actually speak with an IRS representative who confirmed that as the custodial parent with over 50% care, I had the right to claim my child unless I specifically signed Form 8332. They also explained how to handle the situation if my ex tried to file first. You can see how the service works in this video: https://youtu.be/_kiP6q8DX5c - it basically gets you through to a human at the IRS instead of waiting forever.

I have to admit I was completely wrong about Claimyr. After writing that skeptical comment, I was still stuck trying to reach the IRS about my own dependent claim issue. Out of desperation, I tried it yesterday. The service actually worked exactly as advertised. I got a call back in about 40 minutes with an actual IRS representative on the line. The agent confirmed that as the custodial parent with my kids living with me most of the year, my ex couldn't claim them without my signed Form 8332 - regardless of what our informal custody arrangement says. This saved me from a potential audit and having to pay back tax credits I rightfully deserved. I'm still shocked that something actually worked as promised when dealing with the IRS!

The birth certificate actually doesn't matter for tax purposes. When I went through my divorce, my ex tried to claim our daughter every year despite her living with me full-time. The judge in our case made it very clear: it's about where the child physically resides for the majority of the year (183+ days). Document everything - keep a calendar showing exactly which days your child is with you vs. with him. Save receipts for major expenses (medical, childcare, etc.) to show you're providing support. If he files first and incorrectly claims your son, you'll need to paper file your return and be prepared for a longer refund processing time while the IRS sorts it out.

Hey, one thing nobody's mentioned - even if he's not on the birth certificate, has he established legal paternity any other way? In my state, unmarried fathers have to file an acknowledgment of paternity before they have any legal rights to the child at all. If he hasn't legally established paternity, he might not even be able to claim the child regardless of the custody situation. Just something else to consider.