I have many of the same component render on one page, my user can add more of the same child components if they want. When they choose the date within the form element of the child component I only want to change the date of the child component they selected. At the moment it changes the date for all the child components on the screen, can anyone see where I am going wrong?

```
class ParentFixturesComponent extends Component {

    constructor() {
        super();
        this.state = {
            numChildren: 0,
            startDate: moment(),
            id: uuid()
        };
    }

    changeDate(newDate) {
        this.setState({
            startDate: newDate
        });
    }

    onAddMatch() {
        this.setState({
            numChildren: this.state.numChildren + 1
        });
    }

    render() {
        const children = [];
        for (let i = 0; i < this.state.numChildren; i += 1) {
            children.push(<SingleMatchForm startDate={this.state.startDate}
                                           key={this.state.id}
                                           changeDate={this.changeDate.bind(this)}
            />)
        }

        return (
            <Fixtures addMatch={this.onAddMatch.bind(this)}>
                {children}
            </Fixtures>
        );
    }

}

export default ParentFixturesComponent;

```

Child component

```
class SingleMatchForm extends Component {

    handleChange(params) {
        this.props.changeDate(params);
    }

    render() {
        return (
            <div className="row">
                <div key={this.props.id} className="form-group">
                    <label className="control-label col-md-2">New Match</label>
                    <div className="col-md-6">
                        <DatePicker
                            selected={this.props.startDate}
                            onChange={this.handleChange.bind(this)}/>
                        <div className="section-divider mb40" id="spy1"> </div>
                    </div>
                </div>
            </div>
        );
    }

}

export default SingleMatchForm;

```